UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Crystallography of low alloy iron martensites Jeffrey, Paul William 1967

You don't seem to have a PDF reader installed, try download the pdf

Item Metadata

Download

Media
[if-you-see-this-DO-NOT-CLICK]
UBC_1967_A6_7 J37.pdf [ 8.02MB ]
Metadata
JSON: 1.0104520.json
JSON-LD: 1.0104520+ld.json
RDF/XML (Pretty): 1.0104520.xml
RDF/JSON: 1.0104520+rdf.json
Turtle: 1.0104520+rdf-turtle.txt
N-Triples: 1.0104520+rdf-ntriples.txt
Original Record: 1.0104520 +original-record.json
Full Text
1.0104520.txt
Citation
1.0104520.ris

Full Text

CRYSTALLOGRAPHY OF LOW ALLOY IRON MARTENSITES by  PAUL WILLIAM JEFFREY A THESIS SUBMITTED IN PARTIAL FUIJILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN THE DEPARTMENT OF METALLURGY  We accept this thesis as conforming to the standard required from candidates for the degree of MASTER OF SCIENCE  Members o f t h e Department o f M e t a l l u r g y  THE  UNIVERSITY OF BRITISH COLUMBIA  April, 1967.  In p r e s e n t i n g requirements Columbia, for  by t h e  thesis  in p a r t i a l  f o r an a d v a n c e d  degree  at  I agree that  reference  tensive  this  the  and s t u d y .  copying of  this  Library I  further  thesis  Head o f my D e p a r t m e n t  for  the  scholarly  cial  not  Department  of  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, C a n a d a Date  May  5,  1967  Columbia  freely  the  British available  permission for  p u r p o s e s may be  this  thesis  be a l l o w e d w i t h o u t my w r i t t e n  Metallurgy  of  representatives.  copying or p u b l i c a t i o n of  shall  it  agree that  understood that gain  University  s h a l l make  o r by h i s  f u l f i l m e n t of  for  It  exgran  is  finan-  permission.  ABSTRACT  The morphology and crystallography of the martensite  transformation  in pure iron and low alloy Fe-C, Fe-Mn, Fe-Hn-Si, F -Ni steels which contain e  no retained austenite was studied.  Single surface trace analyses by  transmission electron microscopy on directions parallel and normal to the martensite substructure were found to be consistent with the martensite crystals having the form of plates rather than needles. The directions normal to the martensite substructure plates were consistent with a £ l 4 5 J  M  habit plane. Optical studies of the martensite surface shears within prior austenite grains revealed that 4 shear variants generally occur. However grains containing 5 or- more shear variants could be found which appears to suggest an austenite habit plan© close to bint different from { i l l ] * » A single surface trace analysis of the martensite surface shears using the austenite annealing twin vestiges to orient the grain was consistent with an austenite habit plant ~ 7° from [ i l l ]  A  ,  Two inhomogeneous shear systems were found to predict the experimental results when applied to the Wechsler, Lieberman, Read theory of martensite transformations. The  (ill},  They are  (l00^[0lo]  A  and  (lll) [ll2] A  A  system i s to be generally preferred as i t s predicted habit  planes ( 7.12° from [ l l l }  A  and 5.03° from (l45^  M  are more consistent w i t h  the trace analyses. Preliminary work included an investigation of the maraging properties of the Fe-Mn-Si system.  ACKNOWLEDGEMENT The  author  research director,  would l i k e  t o extend  h i s s i n c e r e thanks t o h i s  D r . D. Tromans f o r h i s g u i d a n c e a n d h e l p d u r i n g  this  work.  The faculty,  staff  freely  g i v e n a d v i c e a n d a s s i s t a n c e b y members o f t h e  and s t u d e n t  b o d y was i n v a l u a b l e t o t h e c o m p l e t i o n  of this  work and i s g r e a t l y a p p r e c i a t e d .  The  financial  support.provided  by t h e N a t i o n a l R e s e a r c h  C o u n c i l and Defence R e s e a r c h Board i s g r a t e f u l l y  acknowledged.  TABLE OF CONTENTS  Page I.  INTRODUCTION AND AIM OF INVESTIGATION  1  II.  GENERAL FEATURES OF MARTENSITE TRANSFORMATIONS  2  III.  PREVIOUS WORK  4  IV.  EXPERIMENTAL.  8  V.  1. Materials  8  2. Alloy Preparation  8  3.  Alloy Analysis  8  4. Surface Shears  9  5.  10  Electron Microscopy  RESULTS  11  1. Surface Shears  VI.  H  2. Electron Microscopy  11  3.  12  Calculations  DISCUSSION OF RESULTS  38  1. Surface Shears  38  2. Electron Microscopy  40  3.  41  Calculations  VII.  CONCLUSIONS  VIII.  SUGGESTIONS FOR FUTURE WORK  IX.  APPENDICES (I)  ........  47  Wechsler, Lieberman, Read Phenomenological theory of martensite transformations  (II)  45  48  Investigation of Maraging Properties of Fe-Mn-Si System  60  TABLE OF CONTENTS ( c o n t i n u e d ) Page  1.  X,  General ...  .  60  2. Alloy P r e p a r a t i o n and Analysis  62  3.  63  Results •  4. Discussion of Results  67  5. Future Work  71  REFERENCES  79  LIST OF FIGURES Plfl'i. No. 1  Ian Variation ©f Calculated Martensite Habit Plan© vdth Vj sN/S  2  ti>i•>l••ll  • ( ll• •a«i ••i••>liM  24  •l iiilil•t i  Varlatien ©£ Galeulatgd Auitmite Habit Plant vdth \/j  S\/S  IIIy1II I I M I  I t l  1 1 1 > N I I H I • • i I 1 I t >1 M  l l l l  Martensit© Surface Shears. 1060 X  24  3  Pure Iron.  4  Pure Iron. Martensite Substructure. 29000 X,.......  25  5  F -0.06$ G. Martensite Surface Shears.  26  6  F ~0.06$ C, Martensite Substructure.' 29000 X.  26  7  F©-0.17$ G, Martensite Surface Shears.  27  8  Fe-0,17# C. M a r t e n s i t e S u b s t r u c t u r e .  9  Fe-6.C# M .  10  F -6.0/S Mn. M a r t e n s i t e S u b s t r u c t u r e .  11  Fe-1.7% Si-7.83# Mn.  12  F ~l„7$ Si-7.83$ Mn. M a r t e n s i t e S u b s t r u c t u r e . 29000 X  29  13  Fe-10.79# N i .  30  14  Fe-10.79^ N i . M a r t e n s i t e  530 X  e  e  n  1430 X..... 29000X  Martensite Surface Shears.  e  1100 X . . . .  29000 X  M a r t e n s i t e S u r f a c e S h e a r s . 1060 X  e  Martensite Surface Shears.  Substructure,  1060 X . . . . ,  29000X.....  25  27 28 28  29  30  LIST OF FIGURES (continued)  Fjg. No„ 15  Page Fe-„r$ C.  Austenite Annealing Twin vestiges  within Prior Austenite Grains  ...........  31  16  Pure Iron: Single Surface Trace Analysis (Directions)  32  17  Pure Iron: Single Surface Trace Analysis (Normals)  32  18  Fe-.06# C.  Single Surface Trace Analysis (DirectiorB )  33  19  Fe-,06# G,  Single Surface Trace Analysis (Normals)  33  20  Fe~.17$ G.  Single Surface TraeeAnalysis (Directions)  34  21  Fg-.17# G.  Single Surface Trace Analysis (Normals)  34  22  F§-6.0$ Mn.  Single Surface Trace Analysis (Direetiens)  35  23  Fe-6,G$ Mn.  Single Surface Trace Analysis (Nornals)  35  24  Fe«l.?$ Si-7«83$ Mn,  Single Surface Trace Analysis  (Directions)•i«ai>«>••>i>•M > >  25  Fe~l.?g Si-7.S3$ Mn.  »  M »«>••> < 1 • • M u  36  Single Surface Trace Analysis  (Normals)•••^••••••••••o«»ao»»««*«»*****«»«*»****««*  3o  26  Fe-10.79^ Ni. Single Surface Trace Analysis (Directions) 37  27  F -10 79#Ni. Single Surface Trace Analysis (Normals)  37  28  Relation Between b.c.t. and f.c.c. Unit C e l l s , . . . . . . . .  48  29  Orthogonal Basis Formed by unit vectors 4*/v,^ .......  51  30  S l i p Shear "g"  51  31  T y p i c a l Massive M a r t e n s i t e S t r u c t u r e .................  64  32  Fe-Mn and F e - N i B i n a r y Phase Diagrams.................  72  33  F e — S i B i n a r y Phase Diagram.............................  73  34  Fe-1.0% S i ~ 4 ° 5 $ Mn. A g i n g Curves......................  74  35  Fe-6.0$ Mn.  74  36  F e - 1 . 7 $ S i - 7 „ 8 3 $ Mn.  e  9  in B a s i s D e f i n e d by ^,v: w }  A g i n g Gurves ............................ A g i n g Gurves  75  LIST OF FIGURES F J K » No  (continued) Page  A  37  F e - 4 . 0 $ S i - 8 . 0 $ Mn.  38  Fe-4„79# S i -  39  F e - 5 , 1 5 $ S i - 9 . 4 3 $ Mn.  40  Fe-5.93$  41  Fe-6,3C# S i - 1 9 , 4 0 # Mn.  42  Fe~2.5$ S i - 6 . 0 $ Mn~0.5$ T i .  s  i  8.08$  A g i n g Curves . . . . . . . .  Mn.  75  A g i n g Curves  76  Aging. C u r v e s «  76  - 1 3 . 5 8 $ Mn. A g i n g Curves  77  A g i n g Curves.  77  A g i n g Curves  78  1  LIST OF TABLES Table No.  Page  1  F&-»17# C, Annealing Twin Vestige Analysis.  2  Fe-,17^ 0. Annealing Twin Vestige Analysis  13  3  Fe-6.0$ Mn.  Annealing Twin Vestige Analysis.....  14  4  Pe-6.C# Mn.  Annealing Twin Vestige Analysis..........  14  5  Pure I r o n ,  S i n g l e S u r f a c e Normal A n a l y s i s . . . . . . . . . . . .  15  6  Fe-,06# 0,  S i n g l e S u r f a s © Normal A n a l y s i s . . . . . . . . . . . »  16  7  Fe*-, 17$  S i n g l e S u r f a c e Normal A n a l y s i s . » » . , » « • . . . .  17  8  Fe-6»0$ Mn.  9  Fe-1.7#  10  Fe-I0.79$ N i ,  11  Comparison o f S i n g l e S u r f a c e D i r e c t i o n A n a l y s i s w i t h  12  C a l c u l a t e d v a l u e s o f d i s l o c a t i o n shear (g)  C,  S i n g l e S u r f a c e Normal A n a l y s i s . . . , . « . . . * *  d e f o r m a t i o n (S) 13  .....  Mn. S i n g l e S u r f a c e Normal A n a l y s i s . . . S i n g l e S u r f a c e Normal A n a l y s i s , . . ,  and shape  13  18 19 20  22  f o r two c h o i c e s of the inhomogeneous shear  C a l c u l a t e d p a r a l l e l i s m between i n d i c a t e d shear elements f o r two c h o i c e s o f the inhomogeneous s h e a r , , . . . . . . . . . . . .  22'  LIST OF TABLES  (continued);  T a b l e No. 14  Page Calculated d i r e c t i o n cosines f o r austenite martensite  (%)  (H/0  h a b i t p l a n e s f o r two c h o i c e s of  and the  inhomogeneous s h e a r < > o < > o > B o o o o e o « o » o e « o i > * o o » < > > » » » o « o 0  15  23  C a l c u l a t e d a n g l e s between g i v e n p l a n e s f o r two c h o i c e s o f t h e inhomogeneous shear  < > . o » « • » < > . o«»  16  A n a l y s i s of A l l o y s i n Weight Percent  17  Structures  present a f t e r  a  65  c o o l i n g from t h e A u s t e n i t e  £^G£P_On o o o o o e o o • o o o « o o o o « « o o c o o e e e o o o o * « o o o o o o o e o s e * « « o  23  66  INTRODUCTION AND AIM OF INVESTIGATION This work began as an examination of the transformation substructure and aging characteristics of the martensitic Fe-Mn-Si alloys.  The similarity  between the Fe-Mn and Fe-Ni binary phase diagrams suggested that a Fe-Mn base maraging steel could be developed i n analogy to the commercial Fe-Ni maraging steels.  While suggestions of a martensite aging reaction were found the  work was largely fruitless; and so i t was decided to terminate the aging studies and concentrate on the crystallography and morphology of low alloy ferrous martensites i n general. The decision to concentrate on the crystallography and morphology was strengthened by the fact that preliminary studies on the substructure showed deviations from what was generally accepted i n the literature*  The habit planes i n a number of these low alloy martensites were  determined.  The phenomenological theory of iron martensites as given by  Wechsler, Lieberman, and Read was used i n an attempt to theoretically explain the experimental results. The body of the thesis considers the work on the crystallography and morphology while Appendix II contains the preliminary studies carried out bn the aging characteristics.  - 2 -  GENERAL FEATURES OF MARTENSITE TRANSFORMATIONS Some alloys exhibit dual behaviour i n that they can transform into different structures depending on the cooling rate.  For example, i n low nickel  steel with an a i r cool there appears a structure formed by a nucleation and growth process known as equiaxed alpha. But at much higher cooling rates the above nucleation and growth may be too slow and the large driving force (free energy) may become sufficient to cause a shear type of transformation. This i s called a martensitic transformation and involves the cooperative movement of many atoms. Evidence that martensitic transformations do not involve atomic interchange l i e i n the facts that the product phase i s of the same composition as the parent, and that alloys already ordered remain ordered after the transformation. A special kind of martensitic transformation i s mechanical twinning where the driving force i s deformation rather than i n ternal free energy. The experimental observation most commonly associated with martens i t i c transformations i s the t i l t i n g on the surface of a sample which was polished before quenching to martensite.  This observed- t i l t i n g preserves  lines (vectors) as lines and planes as planesj for example, a scratch made on a surface before transformation w i l l show no observable discontinuity where i t crosses the boundary from parent to product phases,  Hence i t appears  that the product i n a martensite transformation i s coherent with the parent* The interface, or plane of contact, between the parent and product phases i s called the "Habit Plane"; i t i s the plane of the lattice along which the martensite plates form. Another experimental feature used to identify a specific transformation i s the "Orientation Relationship" which states the parallel planes and parallel directions i n the parent and product phases.  Rational habit planes or rational pairs of parallel lines and planes  are not predicted by current martensite theories.  - 3There are two common types of martensite formed, massive and acicular. Acicular martensite i s found i n F -Ni (30 - 33$ Ni) and F -C ( % C > 0„6) e  e  binaries1 both acicular martensites are characterized by retained austenite and a twinning shear mode. When the amount of solute (substitutional or i n t e r s t i t i a l ) i s sufficient so as to suppress the equiaxed (X structure but not so much as to form the acicular structure there appears massive martensite,,  A polished .surface after a massive martensite transformation appears  as many shear plates with only a few unique orientations enclosed within the thermally etched prior austenite grain boundaries. Under the electron microscope i s observed many parallel martensite plates whose thickness i s of the same order as the shear platesj but the relation between the two i s not fully understood,,  Within the martensite plates large tangles of dislocations are  seen, hence the reason for considering the dislocation shear mode to be operative.  The boundary between the martensite plates i s irregular and wavy  and could be due to small distortions i n the habit plane.  It should be noted  that the shear plates which form on the polished surface necessarily have different boundary conditions than plates formed within the specimen and hence one must be careful ln interpreting their significance.  - 4 -  -PREVIOUS WORK The alloys on which most crystallographic studies have been done are those whose M temperature i s below room temperature. g  The reason for this  i s that i n these alloys i t i s possible to obtain the parent (austenite) and product (martensite) phases coexisting, with the product phase of a size large enough to be observable without optical aid.  The habit plane of the  martensite crystal can then be accurately obtained by two surface trace analysis.  The orientation relationship between the two phases can be found  by straddling a martensite plate with an X-ray beam so that the photograph w i l l contain reflections from the austenite as well as from the  martensite.  In alloys with low amounts of solute (both I n t e r s t i t i a l and substitutional) Mf i s above room temperature, hence there i s no retained austenite.  The habit plane can only be determined by the method of single  surface trace analysis which i s very hard pressed in most cases to give an unique result. The orientation relationship cannot be determined without both phases being present. The martensitic transformation has been observed i n pure iron by Jflibby and Parr (l) and Wayman and Altstetter (2),  Wayman and Altstetter  found the surface shears to be consistent with an apparent [ l l l ] ^ habit plane and the martensite crystals to be plate-like rather than needle-like. I t should be noted that needles which l i e along O-IQ)^ can appear to have a pseudo {lll}  A  habit plane ( 3 ) .  One of the definitive papers i n the crystallography of Fe-C i s that due to Greninger and Troiano ( 4 ) .  They found,through a two surface  trace analysis of the twin band vestiges,that i n steels with  %G) 1.4 the  martensite plates were parallel to (25<)} , with 0.4$^S<JU4# the plates A  were parallel to f 2 2 5 J  <49  while in steels with C <JD,4$ the martensite crystals  vrere needle shaped and formed i n a plate-like array along the f U l L  planes.  „ 5 Bowles (5) found that the { l l l } ^ habit plane i s comprised of laths parallel to a <^10lXdirection and i s not therefore a true habit plane.  Kelly and  Cutting (6) by the method of single surface trace analysis found that the long axis of the martensite crystals were parallel to ^ l l l ^ , , while the traces normal to the crystals were not consistent with any particular plane0  Hence they concluded that the martensite crystals are l i k e l y needles  rather than plates assumed then  0  <(lll^  If the Kurdjumov-Sachs orientation relationship i s i s parallel to (110% , This (110% direction has  been reported by other workers (4,5,7). It i s not known for sure whether the crystallography of stainless steels i s the same as low carbon alloys, but work such as that done by Kelly and Nutting support the view.  They found two different types of  martensite, one type as i n high carbon steels and a 20$ Ni - 0.8$ C steel had a plate-like substructure which was internally twinned while the second type as i n low carbon and 1 8 - 8  stainless steels had a substructure com-  posed of so called needles which were not internally twinned. Owen, Wilson and B e l l (8) state that they observed only 4 different massive martensite shear traces within any volume formed from a single austenite grain. the [ l l l \  A  This was taken as evidence that the martensite crystals form on planes. The appearance of the surface shears i n Fe-Mn binaries  has been found to be very similar to those i n Fe-Ni„ Scatter has been observed (9,10) i n crystallographic determinations of the {2591A habit plane,, that i s great&r than that attributable to experimental technique. The scatter i s perhaps partially explainable by slight internal stresses which distort the habit plane, but this cannot be the complete answer as the calculated poles due to such a stress l i e on a curve i n the stereographic triangle, where as observed scatter (lO) i s as great normal to this curve as along i t .  Though q u i t e a number o f phenomenological c r y s t a l l o g r a p h i c t h e o r i e s have been p u b l i s h e d t h r e e o f them have g a i n e d t h e widest acceptance;  they  are  those due t o Wechsler, Lieberman, Read (WLR)  ( l l , 12),  (13)  t h e o r y assumes t h a t t h e h a b i t  and B u l l o u g h , B i l b y  (BB)  (14).  The WLR  plane i s u n d i s t o r t e d and u n r o t a t e d w h i l e t h e BM  Bowles, Mackenzie  t h e o r y assumes t h e h a b i t  plane t o be u n r o t a t e d but does a l l o w s m a l l d i s t o r t i o n s i n t h e r e g i o n o f percent 0  The BB t h e o r y assumes an u n d i s t o r t e d h a b i t p l a n e but enables  parameters t o be r e a d i l y varied,,  other  deformation  accompanying t h e m a r t e n s i t e t r a n s f o r m a t i o n i s , a t l e a s t a p p r o x i m a t e l y ,  16,  17)9  an  Comparisons o f t h e 3 t h e o r i e s a r e c o n t a i n e d i n  (l5,  I n t h e i r o n base m a r t e n s i t e s t h e s e t h e o r i e s have been a b l e t o pre**  d i e t t h e {259^ the  one  A l l t h r e e of t h e s e t h e o r i e s a r e e s s e n t i a l l y  e q u i v a l e n t i n t h a t t h e y a r e based on t h e i d e a t h a t t h e t o t a l shape  i n v a r i a n t plane s t r a i n .  (BM)  {225j^,  and (3,  unless a  10,  1 5% 0  15}^  h a b i t p l a n e s but a r e not so s u c c e s s f u l with  d i l a t i o n o f t h e h a b i t plane i s allowed,,  a t h e o r y by Lieberman and B u l l o u g h that martensite p l a t e s with a  (13)  [22$^  A  Recently  which i n c o r p o r a t e s t h e o b s e r v a t i o n  h a b i t a r e composite ( c o n s i s t of twinned  and untwinned r e g i o n s ) appears t o account  f o r t h e {225?A h a b i t s .  With a l l t h r e e o f the t h e o r i e s i t i s p o s s i b l e t o p r e d i c t t h e a u s t e n i t e and m a r t e n s i t e h a b i t p l a n e s from a knowledge o f t h e l a t t i c e parameters of t h e a u s t e n i t e and m a r t e n s i t e and of t h e s l i p system o p e r a t i v e , slip  system i s used pr d i s g a r d e d on t h e f o l l o w i n g b a s i s s ( l ) t h e  h a b i t p l a n e corresponds  t o t h a t determined  (3)  phase0  Wechsler, Read and Lieberman (19)  [lll}^  calculated  e x p e r i m e n t a l l y (2) the v a l u e s o f  g, t h e l a t t i c e i n v a r i a n t shear, and S, t h e macroscopic small*  A given  shear, must be  relatively  t h e s l i p system s h o u l d be one commonly o p e r a t i v e i n t h a t type o f i n v e s t i g a t e d t h e s l i p systems a l o n g  planes with regard t o t h e i r a p p l i c a l i t y to the  i n t e r e s t t o t h e p r e s e n t work though was  ^225J  A  habit,  Of more  t h e f a c t t h a t t h e s l i p system ( l l l ) ^ | l 2 l ] ^  p r e d i c t s a h a b i t plane c l o s e t o j " l l l ^ p and a l s o has r e l a t i v e l y s m a l l  values of g and S„  Otte ( 2 0 ) investigated a number of different slip systems  and compared the calculated habit planes to those commonly observed experimentally! also considered was the effect which variations i n the volume ratio of martensite to austenite has on the calculated habit planes.  Computer  programs were used by Grocker and Bilby ( 2 l ) with the Bullough and Bilby theory to examine the crystallographic features of martensite reactions i n steels.  One interesting comment they make i s that virtually any habit plane  cou],d be predicted by making a suitable choice of dislocation shear; hence they had to limit their analysis to those shear systems commonly observed i n either the austenite or martensite, A surface martensite which formed at 20 - 30° C above the M  8  temperature f o r the bulk material has been reported by Honma (22) i n I r o n alloys of between 20 and 30% N i ,  Similar results were obtained by Kloetermann  and Burgers (23) i n a Fe - 30.2$ N i - 0,4$  G  alloy.  The surface martensite  was found t o form as needles down t o a depth of from 5 -»30/<.  This surface  martensite has been explained (24) as being caused by a reduction of the strain energy term which i s Introduced i n calculating the c r i t i c a l embroyo size for martensite formation. The question of the presence of a surface martensite was examined within the department on Fe - Ao8$ Cu martensite, Down to a depth of approximately „010 inch the martensite was-observed to be uniform with no distinct surface martensite layer.  - 8 EXPERIMENTAL MATERIALS t The iron stock used has the trade name "Ferrovac E" and was obtained from the Crucible Steel Company of America.  The impurities i n weight percents  were as follows. C .005, Mn .0005,  P .003, S .005, S i .006, Ni .02, Cr .006, V .004,  W .01, Mo .001, Co .006, N .00085,  \  .0030,  \  .000025, Cu .01.  Ferrosilicon was obtained from Esco Refinery of Port Coquitlam. The silicon content was analyzed to be 86.7 wt.$. Electrolytic manganese was used i n preparing alloys, ALLOY PREPARATIONi Four of the six alloys studied were prepared by induction melting under an argon atmosphere,  A fused magnesia crucible was used but because  these invariably crack i t was found necessary to place them inside larger silicon carbide crucibles.  The gap between the two crucibles was f i l l e d with  alumina and sealed with refractory cement. The iron was melted f i r s t , then ftuuoViNG  ADDITIONS  the manganooe and silicon- added portion by portion, waiting 4 to 5 minutes between each portion to allow thorough melting and stirring of the fresh charge. This procedure i s most important as several melts were found to be i n inhomogeneous.  The heats were c h i l l casts into iron moulds. The quantity of each alloy  cast was approximately 300 gms. The Fe - .17$ C alloy used was a commercial mild steel.  The pure  iron "alloy" was Ferrovac E, ALLOY ANALYSIS The compositions of the six alloys studied were analysed to be* (1) Pure iron (2) F - .06$ C (3) Fe - .17$ C e  •  . .  (4) Fe - 6.0$ Mn (5) Fe - 1.7$ S i - 7.83$ M  n  (6) Fe - 10.79$ Ni The Fe- 6,0$ Mn alloy was analysed (along with those listed i n the Appendix II) by X-ray fluorescence, while the Fe - 1.7$ S i - 7.83$ Mn and F  e  - 10.79$ Ni alloys were analysed chemically. The carbon alloys were analysed  by burning a sample of known weight i n pure oxygen, collecting and weighing the CO2 formed, and then calculating the Wt, $ C i n the sample. The method used for th© analysis by X-ray fluorescence i s as f o l l o w s . Six alloys as.listed i n Appendix II were chemically analysed, these were used as standards i n the determination of the calibration chart which compares the ratio of the heights of the manganese K«., Krtipeak and i r o n K/3; peak against percent manganese. The fact that there was a 3rd element present, silicon up to 6 percent, w i l l slightly affect the accuracy of the calibration curve. Specimans used on the X-ray fluorescence unit were approximately x £  M  x  with one face polished on 3/0 grit paper,,  SURFACE SHEARS: The surface shears caused by the martensitic transformation were studied as f o l l o w s .  Samples approximately  trolytically or with diamond paste.  x %  w  were polished either elec-  Samples of pure i r o n , Fe - 06$ C, and Fe 0  ,17$ C were .030 i n . thick while those of Fe - 6.0$ Mn, F© - 1,7$ Si - 7.83$ Mn, and Fe - 10.79$ Ni were about 0,100 i n . thick.  The specimans were sus-  pended i n a dissociated ammonia atmosphere ( 3 % + ^ ) for 1^ hours at a temperature of approximately 1250°C„  The presence of nitrogen i n the atmos-  phere appeared to have no effect on the surface shears formed as specimans which were treated in a pure %  atmosphere gave similar shear configurations.  A soaking time of 1^ hours was used to ensure stabilization of the austenite grain growth.  It was found necessary to quench from a temperature as high as  1250°C because otherwise the austenite grains were so small as to inhibit  - 10 formation of the martensite surface shears. After soaking at 1250 C the specimans were quenched directly into brine, at which time the surface shears formed on the pre-polished surface, ELECTRON MICROSCOPY; Material to be used for electron microscopy was f i r s t hot rolled from the cast thickness of 0.5 inch down to approximately ,040 inch. The surfaces were cleaned of oxide i n a warmed 15$ solution of sulfuric acid i n water and subsequently cold rolled, to obtain a smooth surface, down to a thickness of ,025 inch.  Samples of approximately ^ x | inch were cut from the  sheet, annealed at 1050 C for 1 hour i n a into brine.  atmosphere and then quenched  The sample was then chemically polished down to a thickness of  about ,003 inch i n a warmed solution of the following composition* HCl  20 c.c.  H P0 3  4  20 c.c.  HN0  50 c.c.  CH3COOH  100 c.c.  3  It was necessary to s t i r the solution vigorously so as to ensure an even attack.  Because the chemical polishing solution rapidly decomposes i t must  be discarded after polishing each speclman, Ohoosing the thinnest areas l e f t by the chemical polishing proeess the speclman was electropollshed by the Bollman technique (25) i n a solution of the following compositions Water  7 c.c.  Chromic Acid  25 gms.  Acetic Acid  135 c.c.  The f o i l s were studied using a Hitachi Hu - 11A electron, microscope at an accelerating voltage of 100 KV,  Single Surface Trace Analyses Single surface trace analyses were used t o i n v e s t i g a t e the austenite and-martensite habit planes. The austenite habit plane was i n v e s t i g a t e d using the austenite annealing twin vestiges t o o r i e n t the g r a i n with respect t o the austenite axes.  This can be done by f i n d i n g 3 twin vestiges w i t h i n  any one p r i o r austenite g r a i n and by using the fact that the twinning plane i n the austenite i s ^ l l l ]  . In t h i s a n a l y s i s i t was p o s s i b l e  to obtain any number up t o h traces from one oriented g r a i n .  The  analysis was c a r r i e d out "by o p t i c a l microscope at 200X. Transmission e l e c t r o n microscopy was used t o i n v e s t i g a t e the martensite habit plane.  The zone axis of the plane of the image  was obtained from a selected area d i f f r a c t i o n pattern of the substructure p l a t e under consideration..  Each substructure p l a t e was oriented  by comparing with s p e c i f i c c r y s t a l l o g r a p h i c d i r e c t i o n s on the selected area d i f f r a c t i o n pattern.  RESULTS  SURFACE SHEARS A l l six of the alloys studied were found to undergo a martensitic transformation as evidenced by the presence of surface shears on a speciman polished before quenching.  The surface shears were found to be limited by  the boundaries of the austenite grains which were thermally etched during the austenizing treatment•  Only a small number of orientations to the surface  shears were found within any one prior austenite grain, with 4 being the greatest number commonly observed.  But i n a l l six alloys areas were observed  where 5, 6 or 7 traces were present (figs. 3» 5j 7 9» Hj> ^3^»  appearance  S  of the surface Bhears for a l l six alloys was very similar  0  Tables 1 to 4 give the stated angular measurements made during the single surface trace analysis of the surface shears i n the F© - ,17$ C and F@ - 6,0$ Mn alloys.  Fig, 15 shows the typical appearance of the annealing  twin vestiges, ELECTRON. MICROSCOPY A single surface trace analysis was carried out on a l l six alloys, Th© grsat circles connecting the directions parallel and normal to th© martensite crystals with the aone of the surface, ar© plotted i n Figs, 16, 18, 20, 22, 24, 26 and 17, 19* 21, 23, 25, 27 respectively.  The angles which the  above great circles for directions normal to the crystals make with each of [l00J , foil},,, ( l l l } M  in tables 5 to 10.  M  , {112k, fl45? M »  a n  d the calculated plane*are given  The great circles for directions parallel to the martensite  crystals are compared with the directions <^111^> i n table 11. M  Electron micrographs of the martensite substructure are given i n Figs. 4j> 6, 8, 10, 12, L4. * Calculated plane r e f e r s to that predicted using the system ( 1 1 1 ) V-j- = 1.04 i n the Wechsler, Lieberman, Read, Theory. .  A  [112]  A  with  - 12 CALCULATIONS For the inhomogeneous shears values of "g" (dislocation shear) and S M  ( l U ^ [ll2]^ M  and  (lOo) [oio]^ the A  (Shape deformation) were calculated  as per appendix I for values of Vj of 1.00, 1.03, 1.04 and 1.08866.  The  results are contained i n table 12. The parallelism between close packed planes and directions i n the austenite and martensite for the above slip systems and values of Vj are,'given i n table 13. The calculated habit planes In the austenite and martensite are given In table 14} with the same results plotted i n Stereographies triangles  GRAINS  DEGREES  1  2 •  3  0.5 2.0 0.5 3.0 0.5 . 0.0 0.0 1.0 0.0  Table \  r  GRAINS  4 5 6  2  3  Table.. 2.  0.0 0.0 0.0 2.0 0.5 2.0 0^0 0.0 1.0  GRAINS  7  8  DEGREES  0.0 0.0 4.0 0.0 2.0 2.0 0.0 1.0 .  -  Fe - ,17$C, Annealing twin vestige analysis. Angles are those between surface shear normals and calculated austenite habit plane.  GRAINS DEGREES .GRAINS 1  DEGREES  2.0 0.0 6.0 2.0 2.0 0.0 5.0 4aO 2";o  DEGREES  GRAINS DEGREES  4.0 . 4  5 6  22.fr 2.0 0.0 8,0  7.5  1.0 • 6,0  7  S  2,0 2.0 6,0 2.0 4.0  3.5  2.0 2.0  Fe -,17$G, Annealing twin vestige analysis. Angles are those between surface shear directions and \110) , A  - 14  GRAINS ' DEGREES GRAINS 1 2  3,0 0.0 0.0 0.0 0.0 0.5  3 . 4  DEGREES 1.0 1,0 2.0 1.0 5.0 0.5  GRAINS DEGREES 2.0 1.0 2.0  5  Table 3. Fe- 6.0$ Mn. Annealing twin vestige analysis. Angles are those between surfa<fe normals and calculated austenite habit plane. E  GRAINS DEGREES GRAIN  1 2  Table_4o.  0.0 2.0 3.0 9.5 2.0 4.5  3 4  DEGREES 2.0 ' 5.0 7.0 1.5 . 1.5 8.5  GRAIN 5  DEGREES 0.0 3.0 3.5  Fe - 6.0$ Mn, Annealing twin vestige analysis. Angles are those between surface shear directions  and (l!0) . A  Table 5*  Pure Iron. Single Surface Trace Analysis. Angles given are those between normals to martensite substructure plates and indicated planes.  ZONE  '00l\>  pll\ tint  oiz]  112J  ito?  m  4  DEGREES FROM  fiooj  {110}  fill]  [112]  • 41.5 2.0 16.0 39.5 9.5 15.0 15.0 17.5  3.5 2.0 0.0 2.0 7.0 n.o 11.0 8.0 6.5  3.5 33.0 16,0 10.0 22.0 20.0 16.0 16.0 11.0 7.0 18.0 11.0 10.0 9.0 8.0 0.0 20.0 10.0 8,0  1,0 22.0 9.0 2.0 6.5 0.5 0.5 2.5  19.0  20.5 37.0 37.0 17.0 16.5 15.0 16.0  17.0 8.0 25.0 8.0 6.5 7.0 6.0  2,0  8.0  •  1.0 4.0 0.0 3.5 6,0 10.0 9.0 13.0  9.0 2.0 3.5  5.0 5.5 14.5  •  4.0  1.0 7.5 2.0. 0.0 2.0 3.0 0.5 6.0 2.5  2.0  •• 20.0  10,0  20,0 20,0 13.0  10,0 10.0 4.0  20.0  10,0  {145} 3.0 8.0 4.0 2.0 1.0 2.0 2.0 3.5 4.0 2.0 0,0 0.0 5.0 2.0 1.0 1.0 0.0 2.0 2,0 6.0 5.0 4.0 3.0 8.0  Calculated  1.0 11.0 0.0 2.0 0.0 3.0 3.0 0.0  2.0 1.0 3.0 2.0 10.0 6.5 3.5  . 1.0  0.0 1.5 0.0 n.o 9.0 8.5 8.0 6.0  - 16  Table 6*  F - .06$ C Single Surface Trace Analysis. Angles given are those between normals to martensite substructure plates and indicated planes. e  0  ZONE  {001} {011}  {nil  DEGREES FROM (lOOJ  {lio}  [111]  (112?  {145}  42.5  2.5 4.0 1.0 6.0 7.5 8.0  2.0 16.0  2.0  4.0 3.0 2.0 0.5 0.5 0.5 0.0 2.0 2.5 0.5 0.5 0.0 6.0 3.0 1.0 2.0 0.0 3.5 3.0 2,0 3.0 2.0 6.0 0.0 1.0 0.5  39.0  23.0 7.5  10.5  13.0  {012]  15.5  21.0  21.0  18.0 18.0  [113]  12.0  14.0  16.0  (123] (133?  {014I  1.1151 {135?  16.0 17.5 25.0 32.0 5.0 34.0  10.5  15.0 3.5  12,0  13.0  12.0  10,0 5.5 6,0  6.0 6,5 10.0 1.0 3.5 6.0 8.5 8.0 3.0 6.0 4.0 2.0 9.5 16.0 11,0 5.5 7.0  27.0  8.5  12.0  14.0 18.0 7.5 7.5 6.5 5.5 6.0 16,0  18.0 19.0 20.0 11.0 17.0 22.0 12.0 6,0 3.5 9.5 6.0  3.0 0.0  4.0 8.5 4.0 5.0 3.5 0.5 2.0 1.5 3.5 3.5 3.0 6.0 7.0 7.0 7.0 2.0 1.0 0.0  10.0  8.0 4.0  3.5  3.0  6.5 4.5  Calculate. -  1.5  1.0  2.0 0.5  2.0 2.0  4.0 2.0 1.5 0.0 0.0  1.0  5.0 3.0 2.0  1.0  1.0  1.0 0.0 0.0 0.0  1.0  6,0 1.0  1.0  1.0  - 17  Table ft  Fe - .17$ C. Single Surface Trace Analysis. Angles given are those between normals to martensite substructure plates and indicated planes.  ZONE  {001}  fmj  (012}  {112} {122} {113} (123}  {l33j [115]  {135} {353} (317}  DEGREES FROM  .  ,  fiooj  {110?  {111]  (112]  {145$  Calculated  38.5 35.5 24.0 22.0 19.5 18.5 13.0 14.0 14.0 24.0 26.0 .30.0 6.0 12.0 16.0 10.0 8.0 12.0 11.0 18.0 30.5 15.0 3.0 13.0 18.0 13.0 4.0  6.5 9.5 16.0 2,0 5.5 6.0 9.0 9.5 10.5 1.0 2.0 4.0 3.0 9.0 6.0 7.0 10.0 5.5 6.0 6.0 0.5 12.0 9.0 4.5 6,0 7.5 3.0  6.0 7.5 16.5 26.0 23.0 22.0 15.5 19.0 17.5 0.0 2.0 4.0 24.0 7.5 4.5 16.0 16.0 14.0 14.0 4.5 9.0 0.0 6.0 4.0 3.5 14.0 25.0  4.0 5,5 2.5 8.0 5.0 4.0 2.0 1.0 0.0 10.0 8.0 4.5 12.0 5.0 3.0 4.0 4.0 1.5 1.5 :3.0 3.5 0.0 3.5 8.0 4.5 0.5 14.0  0.5 3.5 6.0 2.5 2.0 3.0 3.0 2.0 0.0 4.0 2.0 1.0 .' 3.0 1.0 2.5 0.0 1.0 0.5 0.5 1.0 1.0 1.0 2.0 2.0 0.5 2.0 0.0  3.0 5.5 2.5 8.5 3.5 2.0 0.0 3.5 2.0 7.0 4.5 • 2.0 1.0 0.0 0.0 5.0 3.0 4.0 4.0 1.0 3.0 1.5 4.5 3.0 2.0 2.5 3.5  .  -  - 18 -  Table 8!  Fe - 6.0$ Mn. Single Surface Trace Analysis. Angles given are those between normals to martensite substructure plates and indicated planes.  DEGREES FROM  ZONE £100} . {coil (on]  t-  -*  {111]  012 {1121  |1227  1331 [l35l  16.5 44.0 39.5 35.0 .. 35.0 35.0 40.0 19.0 19.0 23.5 23.5 21.5 20.0 19.0 17.0 12.5 26,0 26.0 32.5 18.0 6.0 14.0 18.0 24.0 24.0 33.0 28.0 .  {no?  [ml  13.0 2.0 6.0 0.5 0.5 0.5 3.0 14.0 14.0 0.5 0.5 3.0 4.5 7.5 10.0 10.0 4.0 2.0 1.0 10.0 10.0 0.0 4.0 2.0 4.0 2.0 6.5  24.0 0.5 4.0 18.0 18.0 18.0 15.0 10.0 10.0 29.0 29.0 26.0 24.0 21.5 19.0 8.0 3.5 10.5 20.0 20.0 16.0 16.0 14.5 12.0 10.0 12.0 11.0  Calculated 9.0 0.0 2.5 0.5 0.5 0.5 2.5 8.0 » 8.0 10.0 10.0 8.0 6.0 4.0 2.0 2.0 4.5 6.0 3.0 . 10.0 2.5 6.0 3.5 4.0 3.0 2.0 2.5  1.0 5.0 1.0 0.0 0.0 0.0 4.0 3.0 3.0 3.0 3.0 1.0 0.5 3.0 2.0 1.0 1.0 2,0 1.0 1.0 0.0 7.0 2.0 0.5 0.5 0.5 0.5  0.5 3.0 2.0 4.0 4.0 4.0 0.0 2.5 2.5 8.5 8.5 6.5 4.5 2.0 1.0 0.0 0.0 0.5 0.0 1.5 2.0 7.0 6.5 0.5 0.5 2.0 2.0  - 19 -  Table 9* Fe - 1.7$ S i _ 7,83$ Mn. Single Surface Trace Analysis. Angles given are those between normals to martensite substructure plates and indicated planes.  ZONE  DEGREES FROM [100J  {001}  fill]  {012} {1I2] J013]. [113]  {115] [l33l {135? (353}  44.5 42.5 41.0 37.5 4.0 3.0 2.0 18.0 33.0 36.0 23.5 22.5 20.5 15.5 13.0 10.5 20.0 21.0 22,0 12.5 18.0 11,0 13.0 18.0 25.0 26,0 26.0 15.0 15.0 30.0 4.0 11.5  .  {no3  fill]  "{112}  {145]  0.0 . 2.5 4.0 7.0 8.0 6.0 4.0 25.0 4.0 0.5 1.0 3.0 7.0 11.0 8.0 7.5 3.0 5.0 6.5 10.0 1.0 5.0 1.0 12.0 11.0 1.0 0.0 7.0 7.5 4.0 .15.0 9.0  0.0 2.0 3.0 6.0 28.0 30.0 32.0 14.5 15.0 20.0 27.0 26.5 23.5 28.5 14.0 12.0 9.5 8.0 15.0 7.0 8.5 13.5 15.0 22.0 5.5 13.5 14.0 4.0 3.5 13.0 10.0 9.5  0.0 1.0 2.0 4.0 18.0 20.0 22.0 0.0 4.0 0.5 9.0 8.5 5.5 0.0 3.5 5.0 6.0 2.5 1.5 4.5 10,0 5.0 2.0 8.0 4.0 5.5 4.5 4.5 4.0 0.0 2.0 3.0  5.5 3.5 2.5 1.0 2.0 4.0 6.0 5.0 3.0 0.0 3.0 2.0 1.5 0.0 4.0 3.0 3.0 1.0 0.5 0.5 3.0 1.0 4.0 2.0 0.5 1.0 2.0 2.0 2,5 2.0 6.0 2.5  Calculated 3.0 1.0 0.5 4.0 7.0 9.0 11.0 11.0 0.0 3.5 1.0 6.5 3.0 2.0 1.5 7.5 0.5 2.5 0.0 0.0 4.5 6.0 6.5 0.0 4.0 6.0 0.0 1.0 1.0 1.0 3.0 2.0  - 20 -  Table 10: Fe - 10.79$ Ni. Single Surface Trace Analysis. Angles given are those between normals to martensite substructure plates and indicated planes.  DEGREES FROM  ZONE  fOOl*  foui  (111}  {012}  {112} \122]  (0131 |H3} /133* {115}  fioo] 35.0 42.0 40.5 39.0 35.0 31.0 29.5 23.5 22.5 20.0 17.5 20.0 20.0 20.0 22.0 23.0 13.5 12.0 12.0 3.5 3.5 10.0 . 13.0 8.5  {110} 7.5 2.5 4.0 5.5 7.5 14.0 9.5 3.0 3.0 6.0 10.0 2.0 3.5 4.0 8.0 4.0 8.0 16.0 14.0 5.5 7.5 6.5 14.0 3.0  [111} 8.0 . 2.0 3.5 4.5 8.0 11.0 10.5 27.0 26.0 22.0 19.0 10.0 9.5 9.0 7.0 4.0 8.0 0.0 0.5 3.0 4.0 12.0 4.0 20.0  {112} 5.5 1.5 2.5 3.0 5.5 4.0 4.0 8.5 8.0 4.0 1.0 5.5 4.0 3.5 0.5 4.5 4.0 5.0 3.5 1.0 1.0 0.0 1.5 8.5  {145} 3.0 4.0 2.0 1.0 3.0 7.0 0.0 2.0 1.0 3.0 3.0 1.0 0.0 0.5 3.0 0.5 3.0 0.0 0.5 0.5 1.0 2.0 5.5 4.0  Calculated 5.5 2.0 0.0 2.0 5.5 8.0 1.0 7.0 6.0 3.0 1.0 0.0 1.5 2.0 0.0 2.0 2.0 1.5 2.0 2.0 3.0 2.0 2.0 2.5  - 21 T a b l e 11.  Single Surface Trace A n a l y s i s A n g l e s g i v e n a r e t h o s e between d i r e c t i o n s o f m a r t e n s i t e p l a t e s and (lll} .  substructure  M  ZONE  PURE IRON  Fe-,06 C  F -.17 C  {on]  2.5  2.5  6.0 . 8.5 18.0  1.0 4.0  4.0  r  i  [on] v.  e  19.5  r  M  ~ i  C  •)  r  •)  C  -\  1.0  3.0 4.0 3.0 6.0  {013I  6.0 3.0 2.0 20.0  fl23l {133} ;  [014] {115J [135?  {353}  5.0 6.0 6.5  1.0 4.0  0.5 2.0 3.5 6.0  4.0 1.0  0.5  0.0 1.5 9.5 10.5  2.0 5.5 6.5 10.5 13.0 9.0 6.0 10.0 12.5 7.0  1.5 3.5 3.5 5.0 8.0 10.0 24.0 7.0 4.0  1.0  1.0  7.0 3.0  16.5 2.0 2.5.  1.0 7.0  9.0  {122]  4.0 1.0 22.5  15.5 18.0 20.0 22.0 2.0  8.0 9.0  2.0 2.0 1.0  5.0 2.5  4.0 10.5 7.0 6.0 10.0 7.0  2.0 6.5 6.5 6.5 10.0  0.5  2.0 3.5 5.0 8.0 11.5 10.0  2.0 3.5 6.5 9.5 3.5 2.0 1.5 2.0 7.0 2.0  8.0  2.0 3.0 11.5  0.0  19.0  Fe-10.79 N i  4.0  15.0 2.0 3.0 4.5 0.5 1.5 5.0 10.0 13.5 16.0 4.0 0.5 4.5  16.5  6.0 8.0 10.0 10.0 18.0  {1125  Fe-1.7 S i 7.83 Mn  15.5;  6.0 8.0 10.0 10.0 18.0  {012J  F e - 6 . 0 Mn  '  1.5 9.0 13.0 20.0 6.0 0.0 1.0  4.0 7.0 8.0 9.5  1.0  2.5  1.5 2.5 7.0  8.5  10.0  - 22 -  (lll) [H2] A  V  A  A  g  S  g  S  .251131 .275677 ,284290 ,353555  .231575 .224947 .222686 .142965  .231566 .251413 .257906 .288672  .466238 .484876 .488759 .516840  I  1.00 1.03 1.04 1.08866  (ioo) [oio]  A  Table 12,, Calculated values of dislocation shear (g) and shape deformation (S) for two choices of the inhomogeneous shear.  (100), [oio]  A  Vi - 1.00 1.03 1.04 1.08866  K  :  ( )„ 011  4.30° 3.50° 3.20° 0.0°  [01l] : [ l l l ] A  0.78° 0.50° 0.48° 0.0°  M  ( l l l ) : (01l)  [011] : [ l l l ]  6.08° 6.60° 6.70° 7.40°  0.95° 0.72° 0.62° 0.0°  A  H  a  Table 13. Calculated parallelism between indicated shear elements for two choices of the inhomogeneous shear.  M  - 23 -  112]  (lOO^OlO],  A  V  %  I  HA  H  M  1.00  -.585345 .470595 .660242  -.665241 -.179279 .724813  ,584838 .521031 .621682  -.035818 .620593 .783283  1.03  -.634885 .479003 .606198  -.715669 -.214413 .664714  .602539 .531538 .595327  -.040314 .643951 .764005  1.04  -.653270 .479698 .585768 .  -.732110 -.228936 .641558  .608047 .534671 .586860  -.041695 .649478 .759230  1.08866  -.816495 .408239 .408256  -.816492 -.408250 .408246  .632453 .547721 .547725  -.048919 .681372 .730303  Table 14. Calculated direction cosines for austenite (%) and martensite (HM) habit planes for two choices of the inhomogeneous shear.  (lll) [ll2] A  V  %  I  1.00 1.03 1.04 1.08866  T a b l e 15  • [Hi]  7.77° 6.75° 7.12° 19.47°  :  H  M  H,[oio]  A  »  ,145]  % • {m}  4.08° 5.43° 5.03° 19.10°  4.17° 3.27° 3.22° 3.97°  H  M  A  J [145]  6.83° 6.73° 6.75° 7.45°  C a l c u l a t e d angles between g i v e n p l a n e s f o r two c h o i c e s o f t h e inhomogeneous shear, %  = A u s t e n i t e h a b i t plane  H$4 = M a r t e n s i t e h a b i t p l a n e  \  ~ 24 -  Fig.  l:  V a r i a t i o n o f C a l c u l a t e d M a r t e n s i t e Habit Plane with Inhomogeneous Shear V  I  1.00  i  1.04 1.08866  3 4  1.03  Fig.  2:  (n4rii2]  A  System  ifioo)[oio] 4  A  5 6  2  7 8  V a r i a t i o n o f C a l c u l a t e d A u s t e n i t e Habit Plane w i t h Inhomogeneous Shear  (ni) [ii ] 4  1.00 1.03 1.04 1.08866  l  2  3 4  Vj.  2  A  System  Hjoio], 5 6 7 8  Vj.  Fig. 3.  Pure Iron. Martensite Surface Shears. 1060 X.  Fig. 5.  F  e  - 0.06$ C.  Martensite Surface Shears. 530 X.  Fig. 7.  F  e  - 0.17$ C  Martensite Surface Shears. 1430 X,  Fig. 9.  F  e  - 6.0$ Mn.  Martensite Surface Shears. 1100 X.  F i g . 12.  F  e  -  1.7$  Si -  7.83$  Mn.  Martensite Substructure.  29000  X  Fig. 13,  F  e  - 10.79$ Ni. Martensite Surface Shears, 1060 X,  F i g . 15.  Fe - .11% C. Austenite grains.  200X.  Annealing Twin Vestiges  within prior  austenite  Fig. 16. Pure Iron* Single Surface Trace Analysis Standard (oOl) Cubic Projection. © Zone axis of plane of image X Direction of substructure plates i n image plane  Fig. 17. Pure Iron : Single Surface Trace Analysis, Standard (OOl) Cubic Projection. O Zone axis of plane of Image X Direction of Normal to substructure plates i n Image Plane.  Fig. 18.  Fe - . 0 6 $ C. Single Surface Trace Analysis. Standard (OOl) Cubic Projection ° Zone axis of plane of Image. X Direction of Substructure plates i n Image Plane.  Fig. 1 9 .  Fe - .06$ C. Single S f Trace Analysis. Standard (OOl) Cubic Projection. © Zone axis of Plane of Image. X P i r e c t i o n of Normal t o Substructure plates i n Image Plane. u r  a c e  - 34 -  Fig, 20. F - .17$ C. Single Surface Trace Analysis, Standard (OOl) C bic Projection. © Zone axis of Plane of Image. X Direction of Substructure plates i n Image Plane. e  u  Fig. 21. F - .17$ C, Single Surface Trace Analysis. Standard (OOl) Cubic Projection. © Zone axis of Plane of Image. X Direction of Normal to Substructure plates i n Image Plane. e  Fig, 22, F - 6,0$ Mn. Single Surface Trace Analysis, Standard (OOl) Cubic Projection. O Zone axis of Plane of Image. X direction of Substructure plates i n Image Plane. e  Fig. 23. Fe - 6.0$ Mn. Single Surface Trace Analysis. Standard (OOl) Cubic Projection. © zone axis of Plane of Image. X Direction of Normal to Substructure plates i n Image Plane.  Fig. 24.  Fig. 2 5 .  F - 1.7$ S i _ 7.83$ Mn. Single Surface Trace Analysis. Standard (OOl) Cubic Projection. ® Zone axis of Plane of Image. X Direction of Substructure plates i n Image Plane. e  Fe - 1.7$ S i - 7.83$ Mn. Single Surface Trace Analysis. Standard (OOl) Cubic Projection. o Zone axis of Plane of Image. X Direction of Normal to Substructure plates i n Image Plane.  Fig. 26.  F - 10.79$ N i Single Surface Trace Analysis. Standard (OOl) Cubic Projection. © Zone axis of Plane of Image X Direction of Substructure plates i n Image Plane.  Fig. 27.  F - 10.79$ Ni. Single Surface Trace Analysis. Standard (OOl) Cubic Projection. O Zone axis of Plane of Image. X Direction of Normal to Substructure Plates i n Image Plane.  e  e  0  - 38 DISCUSSION OF RESULTS  SURFACE SHEARS  The  f o r m a t i o n o f s u r f a c e shears i s used u n i v e r s a l l y throughout  the  t h e m a r t e n s i t e l i t e r a t u r e as an i m p o r t a n t c r i t e r i o n a s t o whether or not a m a r t e n s i t e t r a n s f o r m a t i o n has taken p l a c e .  A l l s i x o f the a l l o y s  s t u d i e d were  found t o form s u r f a c e s h e a r s and f u r t h e r m o r e the shears i n a l l a l l o y s  appear  a l i k e which suggests t h a t t h e mechanism o f the m a r t e n s i t e t r a n s f o r m a t i o n i s similar,,  The  shears were found c o n t a i n e d w i t h i n t h e r m a l l y e t c h e d b o u n d a r i e s  which a r e assumed t o be t h o s e o f the h i g h temperature Owen, Wilsonj, and B e l l  (8)  (8)  a u s t e n i t e phase  0  i n t h e i r study o f the massive m a r t e n s i t e s t r u c t u r e s  i n Fe-Ni s t a t e t h a t they found no more t h a n 4 d i f f e r e n t o r i e n t a t i o n s t o t h e s u r f a c e shears w i t h i n any volume formed  from an a u s t e n i t e g r a i n .  them t o b e l i e v e t h a t t h e h a b i t plane i s l a r g e s t number o f  unique  In t h i s  This led  study 4 i s t h e  shears which r e g u l a r l y appear, but w i t h d i l i g e n t  o b s e r v a t i o n i t i s p o s s i b l e t o f i n d m a r t e n s i t e volumes which have formed a u s t e n i t e g r a i n s w i t h 5 o r more unique  orientations,  from  .From a study of the  photograph which Owen,, W i l s o n and B e l l p r e s e n t as an example o f t h e s u r f a c e shears i n Fe-Ni i t would appear t h a t t h e y came t o t h e i r c o n c l u s i o n p o s s i b l y because  t h e i r a u s t e n i t e ' g r a i n s i z e was  p o s s i b l e shear o r i e n t a t i o n s t o form.  t o o s m a l l , hence not a l l o w i n g a l l From t h e s t u d y o f t h e r e l a t i v e numbers  o f t i m e i n which 4 o r 5 o r i e n t a t i o n s appear i t would seem t h a t the a u s t e n i t e habit plane i s close to' £ The p e r c e n t a g e  L H J  ,  of a g r a i n which has t r a n s f o r m e d m a r t e n s i t i c a l l ' y  depends on the temperature  of t h e a l l o y r e l a t i v e t o t h e M  s  and  temperatures.  As a speciman i s quenched a s m a l l p o r t i o n i s t r a n s f o r m e d i n s t a n t a n e o u s l y t o ma.rtr=rio.ito a n fjoon as the M the o r i e n t a t i o n o i a l l dropped f r o m M  s  R  temperature  subsequent  i s reached,,  I t now  may  w e l l be  m a r t e n s i t e formed as the temperature i s  t o Mf i s determined by t h e f i r s t  c r y s t a l s formed a t  M  go  that  - 39 From strain energy considerations i t may also be that only a small number of the possible different orientations w i l l manifest themselves once the f i r s t ^crystals are formed at M , s  Hence possibly the reason for seldom observing  more than 4 different orientations to the shear traces.  If this were the  case then the fact that only 4 orientations are usually observed would not necessarily imply a habit plane close to { l l l } , A  The appearance of austenite annealing twin vestiges in these alloys complicates the counting of the number of shear orientations within a volume formed from  an austenite grain, but does open up the possibility  of being able to predict the austenite habit plane.  Greninger and Troiano (4)  investigated the low carbon martensites by a study of the austenite twin vestiges and observed a f l l l j  austenite habit plane*  i t was decided to study the twin vestige s in the F  e  With this i n mind  - . 1 7 $ C and Fe - G-,0% Mn  alloys^ which are representative of those examined i n this thesis.  The twin  vestiges gave the orientation of the grain.relative to the austenite axis and hence i t was possible to compare the surface shear normals and directions to specific crystallographic directions. In tables 1 and 3 can be seen the extremely close agreement between the calculated austenite habit plane ( 7 , 1 2 degrees from f l l l } ^ ) and the great circles drawn between the directions normal to the surface shears and the pole of the grain.  Identical results  have also been observed by work within the department (30) on the Fe— 4.8$ Cu martensite. From t a b l e s 2 and 4 i t can be seen that the shear traces a r e . i n the majority o f cases consistent with the directions <^11C>>A «  However the  :  f a c t that there a r c a s i g n i f i c a n t number of shear traces whose directions are not consistent with  <J110)/i would appear to r u l e out the possibility that  the martensite c r y s t a l s are needles whose a x i s i s along which are elongated i n a direction close to  <flld)^  <^lld) , A  Plates  i n the habit plane  could though be consistent with the data i n Tables 2 and 4»  - 40 ELECTRON MICROSCOPY t  From t h e results o f the p o s s i b l e t o s t a t e the martensite  s i n g l e surface t r a c e a n a l y s i s i t i s not  habit plane with assurance.  It i s p o s s i b l e  though to say that t h e m a r t e n s i t e h a b i t p l a n e i s not a plane o f low indices, because iYom the t a b l e s 5 t o 10 i t can be seen that for the martensite habits fioo] ,  , { i l l } and{ll2} a large number of the traces are greater than  5 degrees (the generally accepted criterion) away. A single surface trace analysis i s to a large extent a s t a t i s t i c a l method i n that i t can only hope to predict a given habit plane when a large number of traces (i.e. 25 - 30) are used, and when a l l these traces are consistent with a plane whose poles are grouped into a few discrete regions. I t does appear though that the trace analyses on a l l 6 alloys are consistent with the {l45l The (l45]  habit planes,  M  and calculated (using ( l l l ) [ l l 2 ] with Vj = 1,04)  M  A  A  habit plane gives a slightly better f i t .  must be realized i s that the poles of the {l45^  But what  plane are so situated on the  stereogram that i t i s possible to draw a number of random traces (i.e. 30) and s t i l l have no trace deviate by more than 8 - 9 degrees from a fl45j  pole.  The poles calculated using ( l l l ) ^ p l i ] with Vj ~ 1.04 are distributed similarly to the {145}  M  poles but do not cover the stereogram as thoroughly. Hence  p o s s i b l y t h e reason  why t h e f i t i s not q u i t e as good as for {l45^ .  I n summary, i t can be seen from F i g s . 16, 18, 20, 22, 24, 26 t h a t the poles o f the martensite stereogram. using  (ill].  Such a d i s t r i b u t i o n i s g i v e n b y £l45]  and by the p l a n e c a l c u l a t e d  [112]^ w i t h Vj s 1,04 i n t h e WLR t h e o r y . The  d i r e c t i o n s p a r a l l e l to t h e m a r t e n s i t e  t o be c o n s i s t e n t w i t h in  h a b i t plane must be w e l l d i s t r i b u t e d around the  low G s t e e l s .  n e e d l e s were not  found  <^111% d i r e c t i o n s a s found b y ' K e l l y and N u t t i n g (6)  A s can be seen from T a b l e 11 i t would be p o s s i b l e t o c o n c l u d e  t h a t the t r a c e s a r e p a r a l l e l t o ( l l i ) ^  i f a s u f f i c i e n t number o f t r a c e s were  - 41 not examined, and i t i s s u s p e c t e d t h a t t h i s i s t h e case w i t h t h e work o f K e l l y and N u t t i n g , was  Bowles (5) b e l i e v e d t h a t t h e observed f l l l ^ A  habit  plane  composed o f l a t h s p a r a l l e l t o <^101^ d i r e c t i o n s and hence must be c o n s i d e r e d A  o n l y a pseudo h a b i t p l a n e . $achs i s v a l i d t h e n  <(l01)  I f an o r i e n t a t i o n r e l a t i o n s h i p c l o s e t o KurdjumovA  i s approximately p a r a l l e l t o  <(lll)>  ,  M  But t h i s  work has shown t h a t m a r t e n s i t e c r y s t a l s do not have a common d i r e c t i o n o f Hence a t r u e h a b i t p l a n e c l o s e t o f l l l ^ The  <^111^ .  i s a possibility.  experimental evidence i s i n c o n s i s t e n t with the p o s s i b i l i t y o f  t h e m a r t e n s i t e c r y s t a l s b e i n g n e e d l e s a s no common d i r e c t i o n was f o u n d .  The  f a c t t h a t a common p l a n e was i d e n t i f i e d though does n o t r u l e out t h e p o s s i b i l i t y t h a t t h e p l a t e s may be e l o n g a t e d i n a g i v e n d i r e c t i o n w i t h i n the habit  plane.  CALCULATIONS;  To e x p l a i n t h e o r e t i c a l l y t h e e x p e r i m e n t a l r e s u l t s t h e f o l l o w i n g must be p r e d i c t e d b y t h e t h e o r y . (1) An a u s t e n i t e h a b i t p l a n e c l o s e t o f i l l ] A (2) A m a r t e n s i t e h a b i t p l a n e c l o s e t o [l45?N\ (3) An o r i e n t a t i o n r e l a t i o n s h i p c l o s e t o Kurdjumov - Sachs. Items ( l ) and (2) a r e t h e r e s u l t s o f t h e e x p e r i m e n t a l work w h i l e i t e m (3) i s assumed as t h e Kurdjumov - Sachs r e l a t i o n s h i p i s found i n F e - N i  massive  m a r t e n s i t e ( 8 ) and i n low carbon m a r t e n s i t e s ( 2 6 ) , A l s o t h e theory-must  p r e d i c t r e l a t i v e l y s m a l l v a l u e s of g, t h e  s l i p shear, and S, t h e macroscopic  shear, from t h e use o f s l i p  systems which  a r e e q u i v a l e n t t o t h o s e n o r m a l l y found i n e i t h e r o f t h e two phases. I t has been p o s s i b l e t o f i n d two s l i p to  systems which when a p p l i e d  t h e WLR t h e o r y a r e a b l e t o s a t i s f y t h e above requirements; t h e y a r e  (ll4  [Il2J and A  (l00) [010] . A  A  C r o c k e r a n d B i l b y (21) by u s e o f computer programs,  studied  t h o r o u g h l y t h e problem o f p r e d i c t i n g t h e f i l l ] 4 h a b i t p l a n e u s i n g t h e t h e o r y o f B u l l o u g h and B i l b y , mode (lie) [ l l o ] o r t h e  They came t o t h e c o n c l u s i o n  equivalent  M  mode ( l l O j ^ l l C ^ w e r e  that  general  o n l y the  possibilities.  Hence i t was d e c i d e d t o i n v e s t i g a t e u s i n g t h e WLR t h e o r y t h e  (llo) [lloJ M  The  M  which i s eqviivalent t o (lOO^foio]^ b y the  I fi t i s realized;  11  0,2-*1.7  c a n range from  system  correspondence m a t r i c e s .  c a l c u l a t e d v a l u e s o f g" and "S" a r e g i v e n i n t a b l e 12,  t h a t t h e magnitude o f "g"  shear  and o f "S" from 0.14-*1.9  flOo) [oio] a r e  depending on t h e  shear mode, t h e n t h o s e v a l u e s p r e d i c t e d u s i n g  r e l a t i v e l y low.  The s i g n i f i c a n c e o f t h e magnitudes of "g" and "S" a r e n o t  w e l l u n d e r s t o o d ; b u t i t seems r e a s o n a b l e t h a t  "g",  A  A  a measure o f t h e amount o f  d i s l o c a t i o n s l i p , and "S", a measure o f t h e d e f o r m a t i o n n e c e s s a r y t o accomodate the  change i n macroscopic shape w i l l be important f a c t o r s i n d e t e r m i n i n g t h e  energy a s s o c i a t e d  with t h e formation of a martensite p l a t e .  w i l l be d e f i n e d  f a r t h e r on.  I n t a b l e 13 a r e and be  g i v e n t h e c a l c u l a t e d a n g l e s between c e r t a i n p l a n e s  (lOo)^ [old]  d i r e c t i o n s f o r the  A  system.  seen t o be c l o s e t o Kurdjumov - Sachs.  HA i s 3-* 4° from f i l l ] that the  A  while %  system (100) [010JA  The o r i e n t a t i o n r e l a t i o n s h i p c a n From t a b l e 15 i t c a n be seen t h a t  i s ~ 7 degrees from {lh5J  O t t e (20) has a l s o i n v e s t i g a t e d the  fin) [ii2J  4  4  b u t t h e S«  Sachs t h a n f o r  habit plane.  I f we  d e v i a t i o n from [ l l l j ^ t h a n have C r o c k e r and B i l b y t h e system  i s a l s o found t o f i t t h e p r e v i o u s l y  Furthermore t h e  systems  and m a r t e n s i t e bub a g a i n , a s w i t h t h e work of G r o c k e r and  p r e d i c t s v a l u e s of "g" (lObj, [ o i o ]  Hence we see  commonly observed s l i p  B i l b y , he o n l y goes a s f a r a s c a l c u l a t i n g t h e a u s t e n i t e allow a greater  M .  s a t i s f i e s the c r i t e r i o n s .  a  i n the austenite  The parameter  L]  stated criterions.  It  ( t a b l e 12) V h i c h a r e approi&imately a s t h o s e f o r values are only h a l f those f o r  (lOo) [oio] 4  .  o r i e n t a t i o n r e l a t i o n s h i p ( t a b l e l l ) i s c l o s e r t o Kurdjumov -  (lOo) [oioj A  A  .  ^lll]^[li2J  A  p r e d i c t s an austenite  habit  plane  - 43 about 7 degrees (table 15) from { l l l ^ a n d a martensite habit plane within 5 degrees of {l45] . M  By the correspondence matrices (see Appendix I) the systems (lOO^OloJ^ and ( l l l ^ l l i i ] ^ (llO^p.10^ and  can be shown to be equivalent respectively to  (oil) [oilL. M  i t i s seen that systems  Observing that:  a[ll0] =  a/ [lll]  +  a  a [Oil]  a/2 [111]  +  a  =  (llo) jllo]  usual b,c»e, slip mode { o i l ^  M  2  M  and  / 2  / 2  [ill J [lll]  are (oil) |bll|equivalent M M  t o the  (lll%  There are no other slip systems which when applied to the WLR theory predict the experimental results and satisfy a l l  the orlterions,  The variable Vj has been defined asi where! V = volume r a t i o of martensite to a u s t e n i t e S z i n t e r f a c e d i l a t i o n parameter The WLE theory does not recognise the «S but i t s effect can nevertheless be incorporated i n the theory, assumed to be 1,04  In the present work the value of V has been  (20) as this i s the most common value observed,  Xt was  not possible to measure V i n the alloys investigated as there i s no retained austenite at 're'om temperature, . of  ' ,  By varying 8 we are effectively introducing a uniform dilation  the habit plane,  There i s some doubt regarding the validity of the  dilation parameter, 'However i t does appear reasonable that the interface between two phases of different volumes w i l l be distorted i n some way. Whether i t i s compressed or expanded one can not sayj but the limits of 8 are certainly between ,986 and 1,015 which correspond to values of Vj of 1,00 and 1,08866 respectively.  The physical meaning of the values of 8  are  as follows! with 8 z ,9Q6 the "volume" of material at the interface i s under  - 44 -  compression so that the volumes of both phases are the same| with £> = 1.015 we have the atomic packing along close packed directions the same i n both phaseso The purpose of varying & i n this work was twofold, one to see i f the required criterions could be more closely met, and two, to determine i f the uncertainty i n the true value of V would greatly affect the results,, a 1,05 i t can s t i l l be seen from  Though calculations were not done for  tables 12,, 13, and 15 that the calculated data would not vary to any great degree within the range of Vj from 1.03 to l 05e 0  It should perhaps be summarized here the evidence which supports the assumption that the crystallography of a l l six alloys examined can be explained by one treatments (1) Previous workers have found the crystallography of low carbon and stainless steels to be the same, (2) The physical appearance of the surface shears i n a l l six alloys were observed to be the same. The shears i n a l l alloys exhibited at least 5 different orientations. (3) The appearance of the martensite substructure In a l l alloys was identical. (4) At room temperature after quenching no austenite phase i s retained,, (5) A l l the alloys form a  b c Ce 0  o  martensite,,  (6) The martensite t r a c e s p l o t t e d on a stereogram appear to be consistent with the same c r y s t a l l o g r a p h i c planes and d i r e c t i o n s .  CONCLUSIONS (1) The following alloys were observed to form martensite surface shears': Cl) Pure iron (2) F - .06$ C (3) F - .17$ C (4) Fe - 6 . 0 $ Mn e  e  (5) F  e  - 1 . 7 $ S i - 7.83$ Mn  (6) F  e  - 10,79$ Ni  The surface shears suggest an austenite habit plane close to but deviating from  fill]  .  (2) A single surface trace analysis of the surface shears i n the Fe - 0,17$ C and Fe - 6 . 0 $ Mn alloys i s consistent with the habit plane predicted using the WLR phenomenological martensite theory. This habit plane i s 7.12 degrees from  fllllA. The observed direction of the martensite crystals i n the Fe - 0,17$ 0  and Fe - 6 . 0 $ Mn alloys was not found to be consistent with the directions.  (I1Q)A  However this does not rule out the possibility that the martensite  crystals are plates elongated i n a direction close to ^110% i n the habit plane, (3) The martensite habit plane for a l l 6 alloys i s not a low index plane such as a  {OOl} , { o i l ] j { m } > { l l } 2  « he traces were found to be consistent with T  { l 4 5 ^ martensite habit but due to the limitations inherent i n a single surface  analysis this i s not conclusive. 5,03° from  {145}  TheWLR theory predicts a martensite habit plane  .  The directions parallel to the martensite crystals i n a l l alloys were not found to be consistent with the ^-11^  martensite directions. Hence  i t can be concluded that the martensite crystals are not needles whose axis i s along <^111^  M  but are rather plates or plates elongated i n a given direction  within the habit plane. A l l evidence suggests that the crystallography i n a l l 6 alloys i s the same. •  - 46 -  (4) The two inhomogeneous shear systems  (lll)^[ll2]^  and  (lOC^[oio] were A  found to satisfy a l l theoretical and experimental criterions when introduced into the WLR theory of martensite transformations. The system  (lll)„ | l l i J  i s to be preferred as i t generally gives results closer to those desired, (5)  I f i t i s assumed that V = 1,04 then i t i s not necessary to introduce a  habit plane dilation parameter S experimental results.  into the WLR theory to satisfy the  A  - 47 SUGGESTIONS FOR FUTURE WORK There i s a vast amount of work s t i l l to be done to obtain a complete understanding of the crystallography of iron martensites. Some suggestions relative to the type of martensites examined i n this work are. (1) A thorough study of the following features which characterize the surface shears due to the martensite transformation* (a) occurence (b) magnitude of shears (c) number of orientations formed (2) Work on dotorming- the austenite habit planes i n alloys with no retained austenite but with visible austenite annealing twin vestiges. (3) More alloys of different compositions from the 6 investigated should be made up and studied to determine the composition range over which the same crystallographic features are observed. (4) Computer programs should be written so that the effect of variations i n certain parameters within the theory can easily be checked as to whether or not they improve the f i t between theoretical and experimental results.  - 48 APPENDIX I  BAIN DISTORTION AND CORRESPONDENCE MARTICES  A b . c . c . s t r u c t u r e can be formed from a f . c . c . s t r u c t u r e by a cont r a c t i o n a l o n g one f . c . c . a x i s w i t h a c o r r e s p o n d i n g expansion a l o n g t h e other two  axis.  T h i s d i s t o r t i o n i s known a s t h e " B a i n D i s t o r t i o n " .  [ooi] , [001], f  o  O  Fig,  O  28  [OJOl  [fool  - S  [too], Shown i n F i g . 28 i s a b . c . t . c e l l w i t h i n t h e f . c . c , s t r u c t u r e ; by a p p l i c a t i o n of t h e B a i n d i s t o r t i o n we t r a n s f o r m t h e b . c . t . c e l l i n t o a b . c . c , It  cell.  can be seen f r o m ' F i g . .28 t h a t d i r e c t i o n s i n t h e b . c . c , a r e  r e l a t e d t o t h o s e i n t h e f . c . c . phase by t h e e q u a t i o n ;  I I T  o V  0  !  A At, /u  7  o o \ /\ a. j  The p l a n e s i n t h e two s t r u c t u r e s a r e s i m i l a r l y r e l a t e d by!  \  1  v  3  Ii \ 0  T o \/ ur \ a* O  2 /\ ^  ,  p  (M  z  ^  NeRKftu  CoMftoAJCNTS  49 These two m a t r i c e s a r e known as t h e Correspondence  Matrices,  They a r e  a p p l i c a b l e o n l y i n t h e c o n t e x t o f Fig, 28j t h e y would not f o r i n s t a n c e g i v e t h e b ' . c c . m a r t e n s i t e h a b i t p l a n e once t h e f c „ c . a u s t e n i t e h a b i t 0  p l a n e has been found,  THEORETICAL TREATMENT OF MARTENSITE TRANSFORMATION IN STEEL T h i s appendix w i l l attempt to give a simplified  non-rigorous  treatment of the theory of martensite transformations following closely the notation and treatment as used by Wayman (3).  In this appendix the austenite  (f,c,c,) basis and martensite (b,c,c) basis w i l l be denoted by the subscripts n  f"  and "b" respectively. First to define a few of the symbols and terms used* (1) A matrix w i l l be represented by a capital letter, i.e. A,R , (2) A vector w i l l be represented by symbols such as (3)  %,  The transpose of a vector or matrix w i l l be identified by priming, i.e. Transpose As A', . The operation of transposing a matrix simply interchanges rows and columns. Suppose"  A  =  A B C D  A C A' = B D  then  (4) V e c t o r s w i l l be r e p r e s e n t e d by columns.  F o r example, suppose  t h e v e c t o r r has components u, v, w thens  \M  \  The t r a n s p o s e o f a v e c t o r  we way (5)  as m a t r i x , i . e .  1  i s d e f i n e d i n t h e same  —  . \  . 1  ^>  w  y  When the components o f a v e c t o r a r e used, t h e s e components must be g i v e n as t h e d i r e c t i o n c o s i n e s .  1  with  + ^  +  w  *  "=  1  (6)  By a "Change o f B a s i s " we simply mean t h a t we a r e e x p r e s s i n g t h e components o f a v e c t o r f o r i n s t a n c e , r e l a t i v e t o a new c o o r d i n a t e system.  T h i s treatment w i l l be based on Wechsler, theory o f martensite transformations.  Liebermann, Read (WLR)  T h i s t h e o r y makes p o s s i b l e t h e c a l c u l a t i o n  of t h e h a b i t p l a n e ( i n t h e a u s t e n i t e & m a r t e n s i t e ) and t h e shape d e f o r m a t i o n from a knowledge o f t h e l a t t i c e  parameters  and t h e s l i p system o p e r a t i v e .  The fundamental  treatment  o f t h e f . c . c . and b . c . c . s t r u c t u r e s concept u n d e r l y i n g t h e WLR  i s t h e e x i s t e n c e o f a common u n d i s t o r t e d p l a n e between t h e p a r e n t  ( a u s t e n i t e ) and product  (martensite) structures.  The B a i n d i s t o r t i o n does not l e a v e a common u n d i s t o r t e d p l a n e ( t h e h a b i t p l a n e ) between t h e f . c . c . and b . c . c . s t r u c t u r e s , and i t i s t h e r e f o r e n e c e s s a r y t o combine with t h e B a i n d i s t o r t i o n a c r i t i c a l amount o f s l i p  shear.  The B a i n d i s t o r t i o n and s l i p shear do l e a v e an u n d i s t o r t e d plane b u t t h e y do not l e a v e t h e plane u n r o t a t e d , hence a r o t a t i o n i s i n t r o d u c e d t o r e t u r n t h e plane t o i t s o r i g i n a l  orientation.  The shape d e f o r m a t i o n (P^, an i n v a r i a n t p l a n e s t r a i n ) f o r t h e complete t r a n s f o r m a t i o n c a n be w r i t t e n as t h e product o f 3 m a t r i c e s . = RBP  where s  R - the rotation B s the Bain D i s t o r t i o n P s the C r i t i c a l  First determined.  the matrix  B which r e p r e s e n t s t h e B a i n d i s t o r t i o n w i l l be  I f the contraction i s along  [lOO]^ and [010] t h e b . c . c .  S l i p Shear  [00l]^with e q u a l expansions  along  B  s t r u c t u r e i s obtained$ and i n t h i s case m a t r i x  f  has t h e forms 3 r>  l"l> (1)  B  o  o \  o i - o 0  0  "li  j  O  / leu "73  2  v  \CLV  J  3  b  - 51 Cb >&b  a r e  *  n e  lattice parameters of the martensite.  When the  transformation i s f,c.c.-*b.c.c. C = <2j> . V is"£he volume ratio of martensite b  to austenite, about 1.04 for most f.c.c.  b.c.c. transformations.  The  WLR  theory considers S , an interface dilation parameter, to be unity; the factor i s used, i n the Bowles-MacKenzie theory. Secondly the matrix P which expresses the slip shear must be determined.  Let us assume a shear along the unit vectors i n a plane whose  normal i s parallel to the unit vector 2L ; let a 3rd direction be defined by the unit vector & given by the cross product,  ^ =  * 3f  With these 3 new mutually perpendicular unit vectors (orthonormal vectors) a new basis i n which the shear has a very single form can be constructed. In other words a basis defined by the directions  <g,1fiW. (fig. 29) rather  than by the directions [l00]^ , [Oio]^ , [oOl]^ » h* b e 8  e n  formed.  i  /  tt  /  0  / 4 , • /  /  / f t  /  Fig. 30  Fig, 29  From-Fig.-30:  v'' W  o + ' v +. 0  w' =  0 t o + V...,.  •  In Matrix Form  The subscript "o" or^h^matrix P<»  5  if  AT'  0  /  0  01  r  designates the basis, i . e . the new basis  i s the "o" basis. » Before the product between the two matrices "B" and "P  0  " can be  - 52 formed the two m a t r i c e s must be r e l a t i v e t o t h e same b a s i s . matrix  Hence t h e "B"  must be r e f e r r e d from t h e " f " b a s i s ( f . c . c , b a s i s ) t o t h e "o" b a s i s .  ^.This can be done u s i n g m a t r i x R5  (3) whose columns a r e g i v e n by t h e c o o r d i n a t e  of t h e "o" b a s i s r e l a t i v e t o t h e " f " b a s i s ( 3 ) . / Z(  t  Mi.  (2)  \ ^3  (27,  A " S i m i l a r i t y Transformation" Conversion R  R ,  28)  In other  -u-,  w,  V 7  Wi  V  W  3  3  words \  /  i s ' used t o c a r r y out t h e  • B  0  - R  5  B , R s  Performing t h e m a t r i x m u l t i p l i c a t i o n u s i n g ! 0  Or • v •w •w  — =  1  A  1  •  v  0  IT * W  0  4  =ha  M W ^\ 3  Bo  A  =  Now B  0  3  P  V , A  oj, +  -u£  3  A  can be c a l c u l a t e d s  Q  w  ^3  (3)  3  ^ V 3  3  A  w A(A g+^) 3  3  i s d e f i n e d as^  7* + ^ f e —  where s  FL F ~ 0  'tf =  (^3$  +  ^3}  7-\)  3  % + W3A  As the m a t r i x i s going t o be d i a g o n a l i z e d , a symmetric  <X  A  v w A.  R P  Matrix Jo  3  - 53 -  The symmetric matrix Jo  describes the effect of the Bain distortion  and the slip shear g, but the fact that there i s a c r i t i c a l value to the shear g has not yet been taken into consideration. It has been shown ( l l ) that a necessary and sufficient condition for the presence of an undistorted habit plane i s for one of the eigenvalues of the distortion matrix J to be unity. This condition can perhaps be made plausible 0  by the following consideration. The general form of the eigenvalue equation iss A )L —  X X  where  The equation says that i f a matrix A  ^  = Matrix  —  = Vector (eigenvector)  ^  = Scalar quantity (eigenvalue)  operates upon  ' u ' the vector i s changed but not i t s orientation.  a vector _xthe length  Hence i f the eigenvalue  ~#\  i s unity the vector & i s unrotated and unchanged i n magnitude5 the conditions desired. Now forming the equations Jo *  =•  ( J o -  =  %  0  For nontrivial solutions of this system of equations the following condition must be met  Jo  DETERMINANT  V £<• y ] -- 0  From the determinant the characteristic equation (3) i s ( ^ j D =  Q -  -  3  DET  [j.]  T(y)  +  z  =  7 t  *  %  tf[i-i3* v +fvf\ 3  3  Q(tf)  ~  D  =  0  *  + y^[i^^v  3  + ?( ' -  ^3)]  -5kThree eigenvalues  A* ^  c r i t i c a l value  shear g i s  of  ( "h? ) b e u n i t y . equation there  a  r  e  obtained from the  o b t a i n e d by demanding t h a t  Substituting results  characteristic  )w = 1  the guadratic  , D,  Q ,  T,  one o f t h e  into the  f o r the c r i t i c a l  equation.  shear  The  eigenvalues  characteristic  g.  U)  3  A  Z  ^  +  3 *  ~  c  0  c=c-vXr«/)V ,In  general two d i f f e r e n t As  equation,  values  of  g  result.  ' ) has b e e n f o r c e d t o be a f a c t o r i n t h e  the o t h e r two eigenvalues  characteristic  are obtained by d i v i d i n g the  characteristic  ( ^ - I )  equation by To o b t a i n '  (tf)  (5)  + (i-T)O )  x  U s i n g one o f t h e v a l u e s >\  and  ^  c a n be  of g i n the  expression for T, the  eigenvalues  (x" /i J  ( r t  \f,  ) (x / i ) w  ,  w  ^3  .  (x® ® f) r  are  solved for the  can be found as  \ J H~ a  X* 1  or i n explicit, form \ J31  eigenvectors  * Reference  (29)  eigenvalues  have been s o l v e d f o r  J3Z (3,  J33  / x \ y(<)  /  w  /  29)* w i t h the s o l u t i o n s d i v i d e d  uses d i f f e r e n t l y labeled coordinate  simply replace the "2"  subscripts i n ref.  corresponding  follows.  ^3  *  These  other two  s o l v e d f r om e q u a t i o n 5 *  Once t h e eigenvectors  + D = O  v  (29)  with  system,to "3",  use these  solutions  - 55 into 3 cases depending on whether (l) W>, =  0  ( 2 ) W3 = 1 (3)  ^ 3  0,1  The eigenvalues can also be determined by finding a new basis "d" in which the matrix «J  i s diagonal i n form. These diagonal elements are the  0  eigenvalues  )\~, , • "A\ ,  J  0  .  — F Fo  R4- Fj  —  0  R«r  The matrix Rj^ defines the similarity transformation between the "o" basis and the new "d" basis. The columns of R^ are given by the eigenvectors solved for above* i,e*  1" x<  y  (2)  i  (t)  The basic premise i s that in the habit plane any vector 2 must not have i t s magnitude changed by the action of the matrices B and P , this algebraically in the " f " basis'> i'  P'B'B.P*  =  I I  The analagous equation i n the "d" basis would be  I'F/H  =  n  which when written i n explicit forms  o  o  K.  0  y  o  %  )\ /  \/ x \  W  2  y  M u l t i p l y i n g out > x  2  +  (K  - 1 ) /  +  1 -  £  Since >,, equals unity-  y  a r b i t r a r i l y setting  / „  -  1)2'  =  0  Expressing  W-i =  i n t o 3 cases depending on whether (l)  O  (2) W3 = 1  (3)  ^3 3=  0,1  The eigenvalues can also be determined by finding a new basis "d  n  in which the matrix J o i s diagonal i n form,, These diagonal elements are the eigenvalues  )\~, , • )\\ , Jo  —  .  F R> —  R4- Fd Rv  0  defines the similarity transformation between the "0" basis and  The matrix  the new "d basis„ 11  The columns of R^ are given by the eigenvectors solved  f o r above, i . e . "x&> y  l , )  (3)  Z  \  J  The basic premise i s that in the habit plane any vector 2. must not have i t s magnitude changed by the action of the matrices B and P, this algebraically i n the " f " basis? I' P ' B ' B P l  =  11  v..  The analagous equation i n the "d" basis would be  i. F 1  =  d  w  11  which when written i n explicit form?  t  o  o  \/x\ y  P  O  >N3  /  \ I 2  w  M u l t i p l y i n g out X  -+  Since "X, equals u n i t y .  a r b i t r a r i l y s e t t i n g ?•= /  0  Expressing  $6  / =  (6)  Hence one be  1  Where  u n d i s t o r t e d v e c t o r i n t h e h a b i t p l a n e i s ^0,S  y  [l 0,<?"|.  seen by i n s p e c t i o n i s  g i v e n by t h e  The  ;  K , I  j a n o t h e r as  can  normal t o t h e h a b i t p l a n e b, i s t h e n  c r o s s product °  [l,0,0] x [0,£K,f]  =  [0,l,S K] R  Normalizing  There are i n g e n e r a l 4 s o l u t i o n s t o ft values  of g and  (29). "d"  ,  The  , corresponding to the  (d)  degeneracy o f s o l u t i o n s i s d i s c u s s e d by  i s a u n i t vector along  2  Wechsler  the h a b i t p l a n e normal r e l a t i v e t o  the  basis. The  from t h e  eigenvectors  which comprise R^  "o" b a s i s by the m a t r i x  can be r e f e r r e d t o t h e  "f"  basis  R^s  (e)  1  jy!' \ l)  y  \  The  [x  (eJ  }  y^  between the  2] W  f orm  ,1,3  Ax  —  (0  #1  \ I"/  ^3  SCA3  t h e columns o f the m a t r i x which expresses the  "d" b a s i s and  the  "f"  basis,  transformation  Hence the h a b i t plane r e l a t i v e t o  the  ' " f " b a s i s i s found from:  /  x  yd)  (9)  \  ^  ,0)  w  a)  1  M  y,<})  ?  fV  \ /  i s a . u n i t v e c t o r p a r a l l e l to t h e h a b i t p l a n e normal to the a u s t e n i t e  relative  axis.  Next must be found the h a b i t p l a n e r e l a t i v e t o t h e m a r t e n s i t e The  directions  [ I To]  . [l  I o]  f j  [0 o /]^  are not  r o t a t e d by the B a i n  axis. distortion.  Sr. as can be seen by the application of the matrix B to these three directions. Furthermore the lattice invariant shear P has no effect on crystallographic directions.  Hence i n the expression for the complete martensite transfor-  mation Pi - RBP> only the rotation R can affect the crystallographic directions. The martensite habit plane i s given as the direction cosines of the habit plane measured from the martensite axis.  The martensite axes ( f i g . 28) are  given by the effect of the rotation R on the three austenite directions. The matrix R can be determined by realizing that i t must counteract the rotation introduced by BP,  If pf i s applied to any two vectors i n the  austenite habit plane, by the use of Euler's theorem (3) the angle of rotation and rotation axes necessary to return these two vectors into their i n i t i a l positions can be determined. As so far only F has been determined, Ff can Q  by obtained by carrying out a transformation from the " 0 " to the " f " basis. This i s done from the equation.  •& = RsF.Ri  (10)  Suppose that V and <r are any two vectors i n the austenite habit plane, then applying Ff:  ,  (11)  = F \?  .(T,  f  = RP cr  then bylEuler's theorem a vector along the desired axis of rotation i s (12)  [Vi-V j X [err - cr] [o-„-  cr ] • [ « ,  y>  _  + V]  ~  The magnitude of t h i s vector determines the angle of rotation 6  0  |r I = TAN  (13)  The desired u n i t vector with components  R  P  Z}  P is obtained 3  by normalizing £ , The general form of the matrix which expresses a rotation by an angle 8 about the unit direction [ R • R, P3 ] can be shown to be (3) R ( l c o s e ) + c o se p,p (i -cos*)-p siwe R - c o s e ) + P SINe (14) a  R  =  a  3  P p,(i-co5e)+ f SIN9  p*(i -lose) + cos e  P P,(l-Cose)-p 5lN0  ftPt(|-COSfl)+P,SWfl  i  3  3  2  2  P P (i-cose)- fiswe l  J  p3(|-Cose)+ Cos 6  Now  as p r e v i o u s l y mentioned t h e p o s i t i o n o f the m a r t e n s i t e axes r e l a t i v e t o P,  t h e a u s t e n i t e axes a f t e r t h e a p p l i c a t i o n o f (15)  R[  l T o  ] = [a,b,c]  R[MO]  a r e g i v e n by«  = [d,e,f]  R[ooi] =  [<3,b,c]  These components form t h e m a t r i x which e x p r e s s e s t h e t r a n s f o r m a t i o n between t h e a u s t e n i t e and m a r t e n s i t e b a s i s .  Hence t h e u n i t v e c t o r p a r a l l e l t o ; t h e  m a r t e n s i t e h a b i t p l a n e fc( ) i s o b t a i n e d from the b  \  The  P  .e  3  h i /  shape d e f o r m a t i o n r e l a t i v e t o t h e a u s t e n i t e axes i s g i v e n by  (17) applying  b c  d  (16)  equations  f?  =  R BP  =  R  F  r  R f> t o t h e h a b i t p l a n e normal i n t h e p a r e n t m a t e r i a l ( a u s t e n i t e ) :  The d i r e c t i o n o f the shape d e f o r m a t i o n i s t h e n g i v e n by v e c t o r subtraction  R Ff  P, it)  (f)  —  The magnitude o f t h e v e c t o r R fp  ^  g i v e s t h e magnitude o f  the shape d e f o r m a t i o n .  Now  t o c o n s i d e r the p a r a l l e l i s m between d i r e c t i o n s and p l a n e s i n t h e  a u s t e n i t e and m a r t e n s i t e * angle Q  between [ l l l ] (1)  Form  f  For example, suppose i t i s d e s i r e d t o c a l c u l a t e the and  A'[ill]  [01l]  b  s  and n o r m a l i z e ,  ( 2 ) Take dot product w i t h (3)  Divide b y / 2 " to obtain  [oil] . b  cos 9 <•  NUMERICAL CALCULATIONS The following i s a suggested procedure for calculating numerically the austenite and martensite habit planes and the shape deformation. (1) Assume a specific slip system of the form and T J equation  (2) Calculate  3  (M, ,  , ^ 3 ) ^ "frl  5  , Vj J  1.  (3) Solve for the two values of g, equation 4. (4) Pick one value for g (usually the smaller) and solve for  7>\ and  \\ ,  equation 5» (5) Calculate the habit plane normal relative to the "d" basis, equation 7. (6) Depending on the value of U/3 calculate the three eigenvectors relative to the "d" basis.  References (3* 29).  See text of appendix,  (7) Refer these eigenvectors to the " f " basis, equation 8. (8) Calculate the habit plane normal i n the " f " (austenite) basis, equation 9. (9) Calculate F  0 s  equation 3.  (10) Calculate F , equation 10. f  (11) Choose any two vectors V , CT i n the austenite habit plane, work out equation 11. (12) Calculate  equation 12. Normalize r.  (13) Calculate & equation 13, (14) Calculate R, equation 14. (15) Work out equation 15. (16) Obtain the martensite habit plane from equation 16, (17) The shape deformation i s determined as given from equation 17 onwards.  - 60 APPENDIX I I  INVESTIGATION OF MARAGING PROPERTIES OF F - M - S j SYSTEM e  n  GENERAL  The t e r m "maraging"  i s used t o d e s c r i b e an age h a r d e n i n g treatment  g i v e n t o a carbon f r e e i r o n m a r t e n s i t e s t r u c t u r e .  s t e e l s 5 t h o s e c o n t a i n i n g 12$  t y p e s o f i r o n - n i c k e l base maraging 18$ N i (31,  33,  34,  35,  36),  20  -  There a r e t h r e e b a s i c  25$  N i (36).  Ni  The h i g h n i c k e l content i s  t o ensure a d u c t i l e m a r t e n s i t e s t r u c t u r e w h i l e supplementary  a d d i t i o n s such  as molybdenum, c o b a l t , t i t a n i u m a r e added t o cause t h e age h a r d e n i n g The most u s e f u l maraging t h e approximate  The t y p i c a l a g i n g  treatment f o r t h i s s t e e l s i m p l y c o n s i s t s o f a one hour a n n e a l a t 800  450°  G .  The  response.  s t e e l t o d a t e has proven t o be t h a t w i t h  c o m p o s i t i o n Fe-18$ Ni-8$ G©-4$ Mo-0.4$ T i .  an a i r c o o l t o room temperature  (32),  degrees  G,  f o l l o w e d by a t h r e e hour a g i n g treatment a t  s t r e n g t h e n i n g appears t o r e s u l t from o r d e r i n g and  precipitation  r e a c t i o n s , but t h e exact mechanism's a r e not c l e a r l y understood and a r e t h e s u b j e c t o f much i n v e s t i g a t i o n . The g r e a t s i m i l a r i t y between t h e i r o n - n i c k e l and iron-manganese b i n a r y phase diagrams a manganese maraging  ( F i g , 32.)  s u g g e s t s t h a t i t might be p o s s i b l e t o develop  s t e e l i n analogy t o t h e n i c k e l maraging  steels  (31~*"3°).  A p a r t i a l s u b s t i t u t i o n o f manganese f o r n i c k e l has a l r e a d y been a f f e c t e d by P a t t e r s o n and R i c h a r d s o n (3?) i n t h a t they d e v e l o p e d a s t e e l o f c o m p o s i t i o n 12.5$  Ni  s  2$ Mn,  8$ Co, 4$ Mo,  u s u a l F e - N i maraging  steels.  0.2$  Ti  s  0.1$  A l which i s comparable  They found t h a t manganese s u b s t i t u t e s  f o r n i c k e l i n a r a t i o o f one p a r t Mn f o r 3 p a r t s N i , t o improve t h e Fe-Ni-^Mn maraging  with the equivalently  They a l s o suggest t h a t  s t e e l s an i n c r e a s e i n Mn a l o n g with a  c o r r e s p o n d i n g drop i n c o b a l t s h o u l d be i n v e s t i g a t e d .  Goldman and Manec  have c a r r i e d out experiments on t h e k i n e t i c s and mechanism  (38)  of hardening i n a  - 61 -  F -12$ Mn-5$ Ni~4$ T i maraging steel, while Keiichi Qhta (39) reports that e  i n a F -4.85$ Ni-2.66$ Mn-2.52$ Si-0.52$ T i steel there i s an increase i n e  hardp.ess from 28 to 53 Rockwell C on tempering 4 hours at 500° G.  Earlier  work by Decker, Eash and Goldman (3l) had suggested that manganese had undesirable effects but this now appears to be erroneous, at least up to the additions reported above. Also Kattus (40) has developed a 3-11$ Mn, 1.5 - 2.0$ S i , 0.6 - 1.25* T i , 0.4 - 3.4$ Mo steel which shows an ultimate strength increase from 85,000 to 160,000 psi after aging for several hours at 480° C. Richardson (4l) discovered that Fe-Mn-Ni alloys without auxiliary hardeners shows the typical increase i n strength after a maraging treatment. The aim of the present investigation was to develop a nickel free maraging steel with the use of manganese and silicon additions. Maraging properties were to be looked for among those alloys which had a soft martensite structure on cooling from the austenite.  The manganese was added to ensure  a martensitic transformation while the silicon addition was to provide the hardening mechanism. As can be seen from the Fe-Si binary phase diagram (Fig. 33), Fe-Si alloys i n the region of 6$ can take part i n an ordering reaction.  The idea was to quench the alloys from the disordered phase ( « )  so that they would s t i l l be disordered, and hopefully, soft at room temperature. Then with the subsequent aging treatment within the ordered  et phase i t was  hoped that the alloys would harden. The maraging properties of the Fe-Mn binary were  also examined. In order to determine the optimum alloy composition the manganese  content was varied from 0 to 20$ with variations ©f silicon between 0 and 6$. The effect o f varying the aging temperature was also investigated.  - 62 ALLOY PREPARATION AND ANALYSIS The materials and the procedure used i n the preparation of the alloys are as given i n "Experimental" of this thesis,  A total of 17 alloys  were cast but five had to be discarded because the composition was not homogeneous. The methods of alloy analysis are the same as those used i n the "Experimental"•  It was not found possible to analyse for silicon by X-ray  fluorescence! hence the Si content was assumed to be correct whenever the Mn content was analysed to be so.  The analysis of the alloys used is given i n  Table.16. Details of preparation of specific alloys are shown on the age hard$n£jng curves Figs. 34 to 42.  Homogenization was carried out i n a  horizontal tube furnace under an atmosphere of dissociated ammonia ( 3 ^ + % ) , Specimans were quenched directly from a vertical tube furnace into brine or water.  Specimans were polished before hardness tests, hence any  effects due to the dissociated ammonia atmosphere should be minimized. The aging curves were obtained by holding the speciman at temperature for a given length of time, quenching i n water, measuring the hardness and then returning the same speciman to the furnace for another predetermined length of time before repeating the process.  No special atmosphere was used  for the aging tests. If there i s a martensite transformation present i n a speciman the cooling curve should show a decrease i n slope at the transformation temperature. A Chromel - Alumel thermocouple was spot welded to the sample which was then heated into the austenite region with a torch. The thermocouple was attached to an oscilloscope which displayed the cooling curve as a function of millivolts and time.  The formation of bubbles on the surface of the speciman when  quenching i n water prevents a smooth cooling curve and hence covers any change  - 63 « in slope. It was therefore necessary to coat the surface of the speciman on the side of the thermocouple with refractory cement. While this procedure reduces slightly the cooling rate i t does allow a smooth cooling curve to be obtained, Specimans for optical examination were lapped progressively down to 3/0 grit paper, then polished with diamond paste. was found to cause pitting.  Polishing with alumina  Etching was performed with a 1$ solution of  HN0 i n alcohol (Nital), 3  Specimans used on the diffractometer were approximately  x $? x £" x  with one face polished with 3/0 grit paper.  RESULTS The two alloys F  e  - 6,0$ Mn and Fe - 1,7$ Si - 7.83$ Mn were found  to exhibit surface shears (Figs. 9 and 11 ) which are the commonly accepted criterion as to whether or not a martensitic transformation has taken place. No other alloys were examined for surface shears.  These two alloys and the  four given below did have the same etched structure (Fig. 3 l )  s  F - 7.3$ Mn Fe - 9.5$ Mn Fe - 1.0$ Si - 4,5$ Mn e  F  e  - 4.0$ Si - 8.0$ Mn  The structure i n Fig. 31 i s very similar to that found i n Fe-Ni martensites by Owen et. a l . (13). None of the alloys given i n Table 16 other than the above six were found to show this martensitic etched structure.  - 64 -  Fig.  The  3 1 : T y p i c a l Massive M a r t e n s i t e S t r u c t u r e . S u r f a c e P o l i s h e d and E t c h e d i n N i t a l .  1 7 5 X.  i d e n t i f i a b l e phases as determined from t h e s t u d i e s on t h e  diffractometer are given i n Table 1 7 . C o o l i n g c u r v e s o f t h e f o l l o w i n g a l l o y s were s t u d i e d : F  e  -  4.79$  S i - 8 . 0 8 $ Mn, Fe -  Fe - 6 . 3 0 $ S i -  19.40$  Mn.  5.15$  s  i-  9.43$  Mn, F  e  -  5.93$  F  e  Si -  Age hardening experiments were c a r r i e d out on a l l e  13.58$  Mn,  The expected c o o l i n g curve a r r e s t d u r i n g a i r  c o o l i n g and water quenching was o n l y observed w i t h t h e Fe - 7 . 3 $ Mn  except Fe - 7 . 3 $ Mn, F  - 7 . 3 $ Hn,  - 9 . 5 $ Mn and F  the age h a r d e n i n g curves o b t a i n e d .  e  - 16.5$  Mn.  alloys  alloy. (Table 1 6 )  See F i g s . 3 4 t o 4 2 f o r  - 65 -  METHOD OF ANALYSIS CHEMICAL  ALLOY 1 .2  X-RAY FLUORESCENCE X  Fe-6.0% Mn  f-  F -7.3$ Mn  X  e  3  F -9.5$ Mn  X  4  Fe-l6.5$ Mn  X  5  Fe-1.0* Si-4.5$ Mn  X  6  Fe-1.7* Si-7,83^ Mn  X  7  F -4.0$ Si-8.0C# Mn  X  8  Fe-4.79# Si_8.08$ Mn  9  Fe-4.79$.Si-9.43^ Mn  X  10  Fe-5.93$ Si-13.58$ Mn  X  11  F -6.30$ Si-19.40$ Mn  X  12  Fe-2.50$ Si-6.0$ Mn-.5 T i  e  e  e  X  Table 16. A n a l y s i s of A l l o y s i n Weight Percent,  X  - 66 ALLOY  COOLING MEDIA BRINE  Al R  Liq.  N  2  OBSERVED STRUCTURE e (b.cc.) (fee.)  1. F -6 OMn  X  X  2. F -7.3Mn  X  X  3. Fe-9.5Mn  X  X  4. Fe-l6.5Mn  X  1  e  a  e  X  6. Fe-.17 Si-7.83 Mn  X  X X  X X  X  10, Fe-5.93 Si-13.58 Mn  X  X  X  X  X  X  ?  X  X  X  11. Fe~6.30 Sl-19.40 Mn  X 1  X  X X  X  9- Fe-5.15 Si-9.43 Mn  X X  X  8. Fe-4,79 Si-8.08 Mn  j 12, Fe~2,5 Si-6,0 Mn~0.5 .Ti  X  X  X X  7. Fe-4.0 Si-8.0 Mn  X  X  X  5. Pe-1 Si-4.5 Mn  X  X X  Table 17, Structures Present After Cooling from the Austenite Region.  - 67 DISCUSSION OF RESULTS OPTICAL AND DIFFRACTOMETER STUDIES Of the f o u r Fe-Mn b i n a r y a l l o y s s t u d i e d the Fe~6.C# Mn, F -7.3# Mn e  and Fe-9o5$ Mn had the t y p i c a l massive m a r t e n s i t e appearance ( F i g , 30) t h e F e - l 6 „ 5 $ Mn d i d n o t . a l l o y s form a b c , c 0  p a r t i a l h.cp.  0  while  F u r t h e r as can be seen from T a b l e 17 t h e f i r s t  i r o n p h a s e , whereas t h e Fe-.l6 5# Mn has a p a r t i a l  3 f.c.c,  0  s t r u c t u r e w i t h t h e presence of t h e b . c . c . phase q u e s t i o n a b l e .  These r e s u l t s a r e i n agreement w i t h T r o i a n o and McGuire (42).  The appearance  o f t h e € - p h a s e i n the Fe-Mn b i n a r y c o m p l i c a t e s t h e s i t u a t i o n and i t  is  not  p o s s i b l e t o form a c o m p l e t e l y analagous range o f a l l o y s t o t h o s e found i n i r o n n i c k e l up t© 33 wt, % ( 8 ).  An a l l o y which forms t h e h . c p ,  a s i m i l a r manner i s Fe=18# C r - 9$ N i „  6 - phase i n  O t t e (43) has a s s o c i a t e d the  presence of s t a c k i n g f a u l t s i n the 18-9 s t a i n l e s s s t e e l w i t h the f o r m a t i o n o f the  € « phases  Mn but i s l i t t l e f o r m a t i o n o f the  The f a c t t h a t  s u s c e p t i b i l i t y t o f a u l t i n g increases with  a f f e c t e d by N i content l e a d s one t o suspect t h a t  the  <?- phase i n t h e Fe~Mn b i n a r y but i t s absence i n t h e  Fe-Ni  binary is attributable to faulting. It the  i s commonly r e c o g n i z e d I n the l i t e r a t u r e  (42, 43^ 45 ,46 )  € ^phase i s i n t e r m e d i a t e i n the t r a n s i t i o n from f . c . c ,  to b . c . c .  As can be seen from T a b l e 17 the a l l o y Fe-6„30# Si-19.40$Mn forms s t r u c t u r e s on an a i r c o o l but on t h e more r a p i d water quench i t structure.  that  structures.  / and €  forms an  &  A l s o an a i r c o o l e d sample of Fe-16.5$ Mn was c o l d worked w i t h  the r e s u l t that the  6 and  <x phases formedo  Hence i n e f f e c t the  following  t r a n s f o r m a t i o n s were observed... % ~*  % +€  Fe-6.30$ Si-19.40$M  % ~* o< 3 _ * t f + € - »  Fe-6.30# 81-19.40$ M 6  +  w  F ~l6,5$ Mn e  A i r Cool  n  n  Water Quenched C o l d Work  These t h r e e equations s t r o n g l y suggest t h a t the  # and  6  structures  £  i s an i n t e r m e d i a t e phase between  0  The t e r n a r y a l l o y s s t u d i e d which d i s p l a y e d t h e massive structure  martensite  ( F i g . 31) were Fe - 1,0$ S i - 4.5$ Mn, Fe - 1.7$ S i - 7.83$ Mn and  Fe - 4.0$ S i - 8.0$ Mn. surface shears; i t  The Fe - 1.7$ S i - 7.83$ Mn a l l o y e x h i b i t e d m a r t e n s i t i c  i s p r o b a b l e t h a t t h e o t h e r two t e r n a r y a l l o y s would have  a l s o i f t h e y had been s t u d i e d . a l l p o s s e s s an  From T a b l e 17 i t  can be seen t h a t t h e s e 3 a l l o y s  OC s t r u c t u r e on a i r c o o l i n g t o room t e m p e r a t u r e .  However  this  f a c t i s not n e c e s s a r i l y c o n s i s t e n t w i t h t h e s e 3 a l l o y s b e i n g m a r t e n s i t i c because most o f t h e o t h e r a l l o y s a l s o have an  CX s t r u c t u r e on a i r  The e x p l a n a t i o n p r o b a b l y l i e s i n t h e s i l i c o n c o n t e n t . t h e F e ~ S l phase diagram ( F i g , 33) t h e r e i a a and a s t h e Fe-Jfe b i n a r y Is  at  cooling.  As can be seen from  If l o o p up t o about 2,5wt$ S i ,  s u f f i c i e n t l y h i g h temperatures a JC-»« t r a n s f o r -  m a t i o n i s o b t a i n e d on quenching Fe-Mn-Si  (Si<^2,5Wt,$) systems.  c o n t e n t s s l i g h t l y over 2.5$ t h e i n f l u e n c e of t h e dominate and t h e t r a n s f o r m a t i o n  At  silicon  ^ Fe-Mn s t r u c t u r e w i l l p r e -  s t i l l f o r m s ; which a c c o u n t s f o r t h e  F - 4 . 0 $ S i - 8,0$ Mn system b e i n g m a r t e n s i t i c . e  A l s o t h i s a l l o y was not  a n a l y s e d f o r s i l i c o n l o s e s on c a s t i n g and hence i t s t r u e s i l i c o n c o n t e n t likely  somewhere between 3.5 and 4 , 0 $ ,  i s reached t h e m a r t e n s i t i c  is  As t h e Fe - 4.79$ S i - 8,08$ Mn a l l o y  s t r u c t u r e no l o n g e r forms on c o o l i n g and i t  appears  t h a t now t h e i n f l u e n c e o f t h e s i l i c o n predominates and t h e e q u i l i b r i u m s t r u c t u r e i s p r e s e r v e d from h i g h t o room t e m p e r a t u r e . the Fe - 5.15$ S i - 9,43$ Mn a l l o y .  T h i s reasoning also holds for  I n t h e two a l l o y s o f h i g h e r manganese  content predominance may be r e t u r n i n g t o t h e Mn as we observe ( F i g , #  5) t h e  s t r u c t u r e i n b o t h t h e Fe - 5.93$ S i - 13.58$ Mn and Fe - 6.30$ S i - 19.40$Mn.  I n the a l l o y o f lower Mn content  (F  e  - 5,93$ S i - 13.58$ Mn) t h e r e i s some  q u e s t i o n as t o whether ;br^not t h e o b s e r v e d (X i s t h e product o f a m a r t e n s i t i c *.,'V>-£'-.i;  t r a n s f o r m a t i o n ; but i n t h e a l l o y o f h i g h e r Mn content t h e f a c t t h a t t h e OC o n l y forms on r a p i d quenching suggests t h a t i t  is martensitic  To c o n f i r m  this i t would be necessary to determine whether or not shears form on the surface of a speciman which had been polished before quenching from high temperatures. No optical or cooling curve studies were made on the Fe-2.5$ Si-6.0$Mn 0.5$ T i alloy but i n analogy to alloys of similar Mn and Si contents i t i s probably safe to assume that the 0( structure formed at room temperature i s martensitic. COOLING CURVES; Of those alloys tested only the Fe - 7.3$ Mn showed a change i n slope i n i t s cooling curve. Because of the experimental limitations i t i s not possible to determine the transition temperature with any more accuracy then to say that i t l i e s somewhere between 360 and 390° C.  This temperature range  was observed with both a i r cooled and water quenched specimans,  Gomersall and  Parr (44) carried out cooling curve experiments i n the same way and obtained comparable results.  As no cooling curve arrest was noticed when water  quenching the Fe - 6,30$ S i - 19.40$ Mn alloy i t would appear not to be martensitic! the optical studies also bear this out. However the"fact that i t s water quenched structure suggests a martensitic transformation shows that more work must be done on this alloy, AGING TESTS 8 The data obtained is presented graphically i n Figs. 34 to 42. A l l of the alloys except Fe - 4.79$ Si ~ 8,08$ Mn showed a tendency to harden. The greatest hardness increase was only 8 Rockwell G -points (Fe - 5*-93$'Si-— 13.58$ Mn) while the average was 2 —>-3 ^c Points.  Kattus (40) has developed  alloys similar i n composition to those examined here which show a hardness increment of some 25 points (Rc 10 to Rc 35). Two of the alloys, Fe - 4.0$ Si-8.0$ Mn and F  e  - 4.79$ S i - 8.08$ Mn do have this hardness but i t was not found  - 70 possible to obtain them i n the soft condition before the maraging treatment. The 4 alloys most extensively studied, Fe - 6.0$ Mn, Fe - 1.0$ Si - 4.5$ Mn, F  e  - 1.70$ S i - 7.83$ Mn, and F  typical type of maraging curve.  - 4.0$ S i - 8.0$ Mn do show a  e  The optimum aging temperature and aging time  for the highest strength was 450° C. and approximately 1/2 hour for a l l 4 alloys.  With aging at 400, 500, and 600° C the same strength was not reached.  Aging at 400° G does not cause the curves to f a l l off appreciably after 4 1  hours as they do with aging at 500 and 600° C,  The f a l l off i n hardness with  high temperature'aging i s probably du© to a breakdown of the martensite ^  !  structure with a reversion to the austenite.  A l l 4 of these alloys are  martensitic after quenching from the austenite. The other alloy which was marteaaitie at room temperature was F§ « 2,5$ S i » 6,0$ Mn » 0.5$ T i , and while i t was net as extensively studied a@ the above four i t did §hew similar maraging curves  8  Th« other 4 alleys whose aging eharaeteristies were .investigated are Fe - 4.79$ i i - 8.01$ Mn, F and Fe » 6.30$ S i - 19«40$Mn,  e  - 5.15 $ S i - 9.43$ Mn, Fe - 5.93$ Si - 13.58Jfifa,  Thegta alloys are probably not marteneitie at 200m  temperature with the possible exception of F© ~ 6,30$ Si - 19.40$ Mn i n the water quenched condition.  The above non**marten@itic alloys lose their hardness  much more slowly while aging at 600° 6 than do the 5 martensitic alloy®. This may be expected as the softening mechanism operable i n the martensitic alloys w i l l not apply here, where the softening i s l i k e l y due to a realignment and annealing out of dislocation©. The slight hardening increment observed for a l l alloys except Fe - 4.79$ S i - 8.08$ Mn, i s probably due to an ordering process involving the silicon.  According to the Fe-Si phase diagram (Fig.  not take place until 6$ S i at 450° C.  33) the ordering should  The fact that the two alloys which show  the largest hardening increment also contain the largest silicon content support  - 71 the fact that silicon i s taking part i n ordering.  Other work conducted  - within the department on the Fe-Si binary i s consistent with the idea thai ordering causes slight hardening.  FUTURE WORK Much work remains to be done on these Fe-Mn base maraging steels i n an attempt to obtain a useful product.  Possible suggestions are as  follows s 1. Continue the systematic investigation of the maraging properties by varying (a) proportions of manganese and silicon (b) aging - temperatures and time, . :  2. Examine the ordering reaction i n the Fe-Si binary i n an attempt to determine i f the silicon addition i s beneficial. 3. Attempt to explain why the Fe-Mn binary with no silicon additions also'shows a hardening increment. 4. Study effects of additional elements such as titanium. 5o Study the occurence and crystallography of the h.cp. i n the Fe-Mn binary.  6 phase  op  Weight Perc ent'' S i l i con Fig, 3 3 ! Fe - S i Binary Phase Diagram,  V  i  1  2  !  L.  3  4  Aging Time, Hours F i g , 3 4 . F - 1,0$ S i - 4,5$ Mn. Aging curves. - Hotrolled 950° C - Annealed 950°- C; l/2 hour, a i r cooled - Curve ( l ) Aged 450° C Curve ( 2 ) Aged 400° C Curve '(3) Aged 500° C Curve ( 4 ) Aged 600° C e  Aging Time, Hours F  i g - 35. Fe - 6.0$ Mn. Aging curves. - H o t r o l l e d 950° C - Annealed 950° C,•1/2 hour, a i r cooled - Curve ( l ) Aged 450° C Curve (2) Aged 40C" C Curve (3) Aged 500° C Curve (4) Aged 600° C  i -=  1  1  2  f  1  1  3  4  i I  1  2 Aging T i e  A g i n g Time, Hours Fig,  36,  1.70$  7.83$  F Si - Hotrolled C„ - Annealed C - Curve ( l ) Aged. Curve (2) Aged Curve Aged Curve Aged e  (3) (4)  950° 950°  M. n  m  A g i n g Curves  1/2 Hour, 4 0 0 ° C. 4 5 0 ° 0. 5 0 0 ° C. 6 0 0 ° C. ?  3  A i r Cooled  Fig.  s  3 7 . F - 4.0$ S i - 8.0$ - H o t r o l l e d 950° C. -Annealed 950° C, l / -Curve ( l ) Aged 400° Curve ( 2 ) Aged 450° Curve ( 3 ) Aged 600° ^ u r v e (4) Aged 500° e  4  Hours M, n  A g i n g Curves*  2 Hour, A i r C o o l e d . C. C. C. C.  26 -  22 -  "i  ±~.  Y  t  Aging Time, Hours Fig. 38. Fe - 4.79$ S i - 8.08$ Mn. Aging Curves. - Homogenized 1100° C, 24 Hours. - Hotrolled 900° C. - Annealed 900° C 1 Hour. Curve (l) A i r Cooled, Aged 600° C. Curve (2) Water Quenched, Aged 600° C. 5  Aging •Time, Hours Fig. 39. Fe - 5.15 $ S i - 9.43$ Mn. Aging Curves - Homogenized 1100° C, 24 Hours. - Hotrolled 900° C. - Annealed 900° C, 1 Hour. Curve ( l ) , A i r Cooled, Aged 600° C. Curve (2), Water Quenched, Aged 600°  1  2  3  4  1  A g i n g Time, Hours Fig.  40. F  - 5.93$ S i - 13.58$ Mn. A g i n g Curves - Homogenized 1100° C, 24 Hours. - H o t r o l l e d 900° C. - Annealed 900° C, 1 Hour Curve ( l ) A i r Cooled, Aged 600° C. Curve (2) Water Quenched, Aged 600° C. e  2  3  4  A g i n g Time, Hours i g . 41. F - 6.30$ S i - 19.40$ Mn. A g i n g Curve - Homogenized 1100° C, 24 Hours. - H o t r o l l e d 900° C. - Annealed 900° C, 1 Hour. Curve ( l ) A i r C o o l e d . Aged 600° C. Curve (2) Water Quenched, Aged 600 e  20  i  I  1  i  i  2  3  i  4  1  - Aging Time, Hours FigV 42.  F -  e  - 2.5$ S i - 6.0$ Mn - 0.5$ Ti. Aging Curves Hotrolled 950° C Annealed 1950° C, 1/2 hour, A i r Cooled. Curve (l) Aged 400° C. Curve (2) Aged 500° C, 0  - 79 REFERENCES  (I)  M. J . B i b b y and J . Gordon P a r r 2  %2) *G, M. Wayman and C  0  J I S I , 202, 1964, 100 - 104.  J. Altstetters  A c t a Met.,  2Q, 1962, 992.  (3) C. M. Wayman: " I n t r o d u c t i o n t o t h e C r y s t a l l o g r a p h y o f M a r t e n s i t i c Transformations" (4) A . B  M a c M i l l a n s e r i e s i n m a t e r i a l s c i e n c e , 1964.  G r e n i n g e r a n d A . R. T r o i a n o s T r a n s . AIME  0  (5)  J  (6)  P. M. K e l l y and J . N u t t i n g s  (7)  R. F. Mehl, C. B a r r e t t a n d D. Smiths  (8)  W. S. Owen, E . A. W i l s o n , T  0  140, 1940, 307.  9  S. Bowles? A c t a C r y s t . , 4, 1951, 162 - 171. J I S I , 122, 1961, 199.  Bells  e  Trans.  AIME, i Q l , 1933, 215.  "High S t r e n g t h M a t e r i a l s " ; S e c o n d  I n t e r n a t i o n a l M a t e r i a l s Symposium, U n i v e r s i t y of C a l i f o r n i a . W i l e y , New Y o r k , 1964. (9)  H. M. O t t e and T. A. Reads  (10), J . F  0  Trans.  AIME, 2Q2, 1957, 412.  B r e e d i s and C, M.Waymans T r a n s . AIME, 224., 1962, 1128.  ( I I ) M. S. Wechsler,  D„ S . Lieberman a n d T, A.Rsads T r a n s . AIME, 122, 1953, 1503.  (12) D, S. Lieberman, M  0  S. Wechsler  and T. A. Reads J , Appl,, Phys. 26, 1955, 473.  (13) J . S. Bowles and J . K. MacKenzies (.14) R. B u l l o u g h and B. A. B i l b y  A c t a Met.  2, 1954, 129.  s P r o c . Phys, Soc. Lond, B, LXLX. 1956, 1276.  (15) B„ A, B i l b y and J . W. C h r i s t i a n s "The Mechanism o f Phase T r a n s f o r m a t i o n s i n Metals"  I n s t i t u t e of Metals  (London) monograph and r e p o r t  s e r i e s No. 18. (16) B, A . B i l b y and J . W. C h r i s t i a n s (17) J . W. C h r i s t i a n s  "The Theory  J I S I , 122, 1961, 122.  o f T r a n s f o r m a t i o n i n M e t a l s and A l l o y s "  Pergamon P r e s s , 1965. (.18) D  e  S. Lieberman and R. B u l l o u g h t  Phys.  Status S o l i d i , 12, 1965, 675.  -SOda)  M  S. Wechsler, T. A. Read and D. S. Lieberman^ Trans. AIMB, £L8, i960, 202.  0  (20) H, M. Ottes  Trans. AIME, 218, i960, 342, Acta Met., % 1961, 678.  (21) A. G. Crocker and B. A. Bilby: (22) T. HonmaJ  J. Japan Inst. Metals, 21, 1957, 51 - 55, 122 - 125, 126 - 128,  263 - 267. (23) J, A. Klostermann and W. G. Burgers* (24) H. Warlimonts Trans. AIME, 221, 1961,  Acta Met,, 12, 1964, 355. 1270.  (25) G. Thomass "Transmission Electron Microscopy of Metals " John Wiley & Sons Inc., 1962, (26#P.. Dornen and W. Hofmanns Arch. Eisenh., 2Q, 1959, 627 - 636. (27) H. Margenau and G  0  M. Murphy1 "The Mathematics of Physics and Chemistry"  D. Van Nostrand Co., Inc. (28) H. Goldsteins "Classical Mechanics", Addison - Wesley Publishing Company Inc. (29) M.'S. Wechsler s Acta Met., 2, 1959 , 793. :  :  (30) D, Tromanss Dept. of Metallurgy, University of British Columbia; Private Communication. (31) B. P. Decker, J. T, Eash, A. J. Goldman? ASM Trans. Quart. I £ , 1962, 58. (32) E. P. Sadowskis ASM Metals Eng. Quarterly, Feb. 1965, 56. (33) J. R. Mihalisins ASM Trans. Quart., £2, 1966, 60. (34) 0 (35) S  o  P„ Miller, W. I. Mitchells  c  Floreen, G R Speichs 0  0  JISI, 201, 1965,  895.  ASM Trans. Quart., jJZ, 1965, 645.  ( 3 6 ) Seminar on Maraging S t e e l s , I n t e r n a t i o n a l N i c k e l Co., A p r i l j 1 9 6 2 . (37) W. R. Patterson, L. S. Richardsons ASM Trans. Quart, 52, 1966, 71. (38) A„ J . Goldman, J . Manenc t ASM Trans. Quart., j>8, 1965, 645. (39) Keiichi Ohtas Technol. Repts., Kansai Univ. 1, ..No. 1, 65 - 71 (1959). (40) J  0  R  0  Kattuss Southern Research Institute, Birmingham, Albama, Private Communication, Sept. 1966,  (41) I»« S. Richardson: Foote Mineral Company, Exton, Penna, Private Communication April, 1966. (42) A. R. Troiano, F. T. McGuire: ASM Trans. Quart., H , (43) H. M. Otte: Acta Met.,  1957,  (44) . W. Gomersall, J . G. Parr: n  U3, 340.  614.  JISI, 201, 1965, 275.  (45) R. P. Reed: Acta Met., iQ, 1962, 865. (46) J . F. Breedis and W. B. Robertson: Acta Met., 1Q, 1962,  1077.  

Cite

Citation Scheme:

    

Usage Statistics

Country Views Downloads
China 6 26
United States 5 0
City Views Downloads
Beijing 4 1
Ashburn 3 0
Wilmington 1 0
Shanghai 1 0
Redmond 1 0
Guangzhou 1 0

{[{ mDataHeader[type] }]} {[{ month[type] }]} {[{ tData[type] }]}
Download Stats

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0104520/manifest

Comment

Related Items