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The zicronium-rich corner of the zirconium-titanium-niobium constitutional diagram. 1958

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THE ZIRCONIUM-RICH CORNER OF THE ZIRCONIUM- TITANIUM-NIOBIUM CONSTITUTIONAL DIAGRAM by Bruce C e c i l Whitnore A thesis submitted i n p a r t i a l fulfilment of the requirements f o r the degree of MASTER OF APPLIED SCIENCE i n the Department of MINING AND METALLURGY We accept t h i s thesis as conforming to the standard required from candidates for the degree of Master of Applied Science. Members of the Department of Mining and Metallurgy THE UNIVERSITY OF BRITISH COLUMBIA January, 1958 ABSTRACT An investigation of the zirconium-rich corner of the zirconium- titanium-niobium constitutional diagram i s described,. X-ray techniques and metallography were used. A high-temperature x-ray goniometer attachment was employed to construct ternary isopleths. Isothermal sections and la t t ice parameter measurements are also outlined. The occurrence of a t rans i t ional 60 -phase identif ied tentatively as tetragonal, i s noted. The ternary constitutional data presented' represent essentially a survey of the zirconium- r ich corner and more detailed results must await further work. In presenting t h i s thes i s i n p a r t i a l fu l f i lment of the requirements for an advanced degree at the Univer s i ty of B r i t i s h Columbia, I agree that the L ibrary s h a l l make i t f r e e l y ava i lab le for reference and study. I further agree that permission for extensive copying of t h i s thes i s for s cho lar ly purposes may be granted by the Head of my Department or by h i s representat ive . It i s understood that copying or publ i ca t ion of t h i s thes i s for f i n a n c i a l gain s h a l l not be allowed without my wri t ten permission. Department of Mining and Metallurgy The Univer s i ty of B r i t i s h Columbia, Vancouver 8, Canada. Date January 6th, 1958. ACKNOWLEDGMENTS The author i s grateful for f inancial aid i n the form of a research assistantship provided by the Defense Research Board of Canada under Research Grant DRB 7510-18. The author gratefully acknolwedges the assistance of Dr. V. Gr i f f i th s , the director of th i s research. Special thanks are due to Mr. R.G, Butters for his design and construction of the high-temperature x-ray unit . The technical advice and assistance of Mr. R. Richter and staff members are also acknowledged. TABLE OF CONTENTS Page -: I . INTRODUCTION 1 A. Purpose 1 1 B. The Three Binary Constitutional Diagrams 2 1. The Pure Metals 2 2. The Zirconium-Titanium Diagram 3 3. The Zirconium^Niobium Diagram 4 4. The Titanium-Niobium Diagram 8 I I . EXPERIMENTAL 11 A. Alloy Preparation 11 B. Heat Treatments 14 C. Metallography 15 D. X-Ray Techniques 16 III . RESULTS 22 A. Metallographic Data 22 B. Lattice Parameters 26 C. Ternary Isopleths 27 D. Ternary Isothermals 33 IV. DISCUSSION OF RESULTS AND CONCLUSIONS 33 V. RECOMMENDATIONS FOR FURTHER WORK 45 VI. APPENDICES A. Related Binary Diagrams of Impurity Elements . . . . . . . . 46 B. Lattice Parameter Calculation by the Method of Cohen . . 52 C. d-Spacings of a-Containing Alloys and the U> -Phase . . . 53 D. Temperature Determination of Phase Boundaries i n One Low Niobium Alloy 56 VII. BIBLIOGRAPHY . . . . . 57 LIST OF ILLUSTRATIONS Figure No. Page 1. The zirconium-titanium constitutional diagram 5 2. Lattice parameters of beta zirconium-titanium alloys 5 3. Lattice parameters of alpha zirconium-titanium alloys 6 4. The zirconium-niobium constitutional diagram 7 5. Lattice parameters of beta zirconium-niobium alloys 9 6. The titanium-niobium constitutional diagram 10 7. Lattice parameters of beta titanium-niobium alloys 10 8. Typical levi tat ion melted-and-cast ingot 13 9. High-temperature x-ray unit furnace with a zirconium radiation shield and the external, water-cooled can 18 10. Specimen plate arrangement for the high-temperature x-ray unit . . . 18 11. View of high-temperature x-ray unit showing the vacuum pumps, power supply, potentiometer and vacuum gauge . . . . . . . . . . 2 0 12. View of high-temperature x-ray unit showing the Geiger-counter scaler, rate meter and recorder 20 13. Lattice parameter versus temperature for hydrogen reduced copper powder as measured i n the high-temperature x-ray unit' . : . . . . . 21 14. d-spacings of one plane versus temperature for pure s i l i c a as measured i n the high-temperature x-ray unit . . . . ." . V . . . . 23 15. 85. 4% Zr - 10.3% T i - 4.3$ Nb as-cast 24 16. Same equilibrated to 450°C 24 17. 76.9$ Zr - 5.6% T i - 17.6% Nb as-cast ' i : . . '* . . . . 24 18. Same equilibrated to 450°C 24 19. 85.4% Zr - 10.3% T i - 4.3% Nb held at 600°C for 24 hours after 1 hour at 900°C. 25 20. Same held at 700°C for 24 hours after 1 hour at 900°C 25 21. 76.9% Zr - 5.6% T i - 17.6% Nb held at 525°C for 70 hours after 1 hour at 900°C 25 22. Same held at 600°C for 70 hours after 1 hour at 900°C 25 Il lustrations (cont'd.) Figure No. Page 23. 64.8% Zr - 31.2$ T i - 4.0$ Nb powder from high-temperature x-ray- unit 26 24. Variation of a and c for a phase i n monotectoid alloys of low niobium content at 450°C 28 25. Variation of a and c for a phase in monotectoid alloys of high niobium content at 450°C 28 26. Variation of ao for |3Nb phase in monotectoid alloys of low niobium content at 450°C 29 27. Variation of a 0 for P^b phase i n monotectoid alloys of high niobium content at 450°C 29 28. Ternary isopleth with niobium constant at 4.5 percent . 30 29. Ternary isopleth with niobium constant at 17.5 percent 30 30. Sample scans showing the transformation of a to 3 31 31. Sample scans showing the monotectoid transformation 32 32. Sample scans showing the growth of the trans i t ion OJ -phase 32 33. (a) Isothermal section at 800°C . . . . 34 (b) Isothermal section at 750°C . . . . . . 35 (c) Isothermal section at 700°C 36 (d) Isothermal section at 650°C 37 (e) Isothermal section at 600°G 38 (f) Isothermal section at 550°C 39 (g) Isothermal section at 500°C 40 (h) Isothermal section at 450°C . 41 LIST OF TABLES Table No. Page 1. Some Approximate Physical Constants for Zirconium, Titanium and Niobium 2 2. Typical Analysis of Crystal Bar Zirconium . . . . . 11 3. Typical Analysis of Crystal Bar Titanium 11 4. Spectrographs Analysis of Niobium Rod . . . 12 5. Composition of Alloys Ut i l i zed 14 6. Heat Treat Schedule for Two Alloys 15 7. Etchants for Zirconium-Titanium-Niobium Alloys 16 THE ZIRCONIUM-RICH CORNER OF THE ZIRCONIUM- TITANlUM-NIOBIUM CONSTITUTIONAL DIAGRAM. I. INTRODUCTION A. Purpose In the past ten years a large amount of research has been directed towards a study of the metallurgy of zirconium due to i t s applications in nuclear reactors. Some usages, however, have been limited by a low creep strength at high temperatures. Thus considerable effort has been made by many groups to determine experimentally the factors affecting the constitutional behaviour of zirconium. The development of versati le alloys follows more easi ly once such knowledge has been gained. This involves primarily the determination of constitutional diagrams as yet quantitatively unpredictable. In an attempt to extend the knowledge i t was decided to determine part of a ternary constitutional diagram of zirconium, u t i l i z i n g titanium and niobium as the second and th i rd components. Niobium was chosen as one component for i t , too, has useful properties applicable to reactor core design. Titanium and niobium were also selected so that this research could be corre l- ated with isothermal transformation, kinetic studies being conducted on the zirconium-titanium-niobium system i n the same Department. The pure metals of the chosen system were also available and the desired alloys could easi ly be prepared by l ev i ta t ion melting techniques. In addition to these factors, the three pertinent binary constitutional diagrams were reasonably well established and would provide a good guide. Also, - 2 - the zirconium-titanium system i s t h e o r e t i c a l l y important and the effect of a t h i r d element on that p a r t i c u l a r binary might then add more information of interes t . A l i t e r a t u r e search showed that no previous work had been reported on the system selected. B. The Three Binary Constitutional Diagrams. 1. The Pure Metals. The s i m i l a r i t i e s between zirconium and titanium are extensive. Both metals have two a l l o t r o p i c modifications, low temperature alpha which i s close-packed hexagonal and high temperature beta which i s body-centered cubic. The t r a n s i t i o n temperatures are s i m i l a r , 862°C i n zirconium and 882°C i n titanium. The melting points are also reasonably s i m i l a r , 1845°C i n zirconium and 1668°C i n titanium. Niobium exists i n the body-centered cubic modification at a l l temperatures below i t s melting point of 2415°C. Table 1 compares approximate values f o r some physical constants of zirconium, titanium and niobium. Table 1 Some Approximate Physical Constants f o r Zirconium, Titanium and Niobium-*- Property Zirconium Titanium ! Niobium a phase (cph) a Q (1) Co (A) C 0/a 0, - 3 phase (bcc) a D (I at 20°C) Atomic No. Atomic Wt. Dist. of closest Approach (A) Density (gm/cc.) 3.230 5.133 1.589 3.59 (extrapolated) 40 91.22 3.17 (a) 6.50 2.950 4.683 1.593 3.235 (extrapolated) 22 47.90 2.89 (a) 4.54 3.301 . 41 92.91 2.859 8.57 Zirconium is a member of the second transit ion series of elements and has two 4 d electrons in the incomplete electronic s h e l l . Titanium, i t s s ister element of the f i r s t transi t ion series, has two 3 d electrons i n i t s outer s h e l l . Niobium, one atomic number above zirconium, has 4 d electron; The theoretical and experimental a l loying behaviour of zirconium has been 'extensively reviewed by P f e i l ? » 3 Qne of the pr incipal features of his theoretical review was his attempt to extrapolate results gained from titanium constitutional diagrams to zirconium systems. This was possible because of the s imi lar i t ies pointed out and many reasonable predictions were made. Of particular interest i n constitutional diagram studies i s the effect of impurity elements on the diagrams. The major contaminants encountered in I this work were oxygen, nitrogen and hafnium. Oxygen and nitrogen pick-up can be avoided only when the best high-vacuum or inert atmosphere techniques are used. The hafnium content of the alloys appeared to be of l i t t l e consequence as i t is completely soluble i n both titanium and zirconium. It i s well known that both zirconium and titanium take oxygen and nitrogen into solution extensively and that no high temperature vacuum treat- ment can outgas the two metals. The effect on the transformation temperature of both metals i s serious, as small amounts of oxygen and nitrogen w i l l s tabi l ize the alpha phase to the melting point. Lesser amounts alter the transformation temperature radica l ly . The related binary diagrams of these impurity elements are presented in Appendix A. 2. The Zirconium-Titanium Diagram. The zirconium-titanium constitutional diagram exhibits a complete series of isomorphous sol id solutions i n both the alpha and beta f i e ld s . The - 4 - diagram presented i n Figure 1 represents the work of Fast'* with s l i g h t modifications by Hayes et al.5 A minimum i n the alpha-beta transformation temperature occurs at 50 atomic percent. On the assumption that the valencies of zirconium and titanium are the same, t h i s result cannot be explained as a B r i l l o u i n zone e f f e c t . Nor can any obvious d-shell interaction effect be suggested. La t t i c e parameter p l o t s , as i n Figures 2 and 3, are l i n e a r f o r both alpha and beta zirconium-titanium alloys and t h i s suggests that ordering effects are not operative. I f the depression i s r e a l , a true explanation f o r i t must be found as one i s necessary f o r a proper t h e o r e t i c a l understanding of the zirconium a l l o y systems. The reaction rates f o r t h i s system are extremely f a s t . Duw@:2° found no depression of the transformation temperatures suggested by the equilibrium diagram of Fast with cooling rates up to 8000°C/sec. At t h i s rate, beta phase could be only p a r t i a l l y retained i n alloys ranging from 30 to 70 atomic percent titanium. 3. The Zirconium-Niobium Diagram. 7 The diagram determined by Rogers and Atkins i s given i n Figure 4. The diagram exhibits a complete series of isomorphous s o l i d solutions i n the beta f i e l d from the melting points to a temperature of approximately 980°C. At t h i s temperature, the c r i t i c a l point for a region of beta s o l i d solution i m m i s c i b i l i t y occurs; the composition parameter being approximately 63 percent niobium. At lower temperatures to 6l5°C, the alloys between 17.5 to 87.0 percent niobium decompose to beta zirconium and beta niobium. Alloys from 6.7 to 17.5 percent niobium decompose to alpha plus beta zirconium between 862°C and 615°C. At 6l5°C, alloys from 6.7 to 87.0 percent niobium decompose mono- t e c t o i d a l l y to a monotectoid of alpha zirconium and beta niobium. A small region of alpha s o l i d s o l u b i l i t y e x i s t s up to 6.7 percent niobium at the 8) TJ cd U bD •H •P C CD O co % <D Q 1795 883 100 to co U CD +3 (D CD t> •H -P 3 Figure 1, The zirconium-titanium constitutional diagram (after Fast^ and Hayes et al^) it Weight percentages are used throughout unless otherwise stated. 100 Figure 2. Lattice parameters of beta zirconium-titanium alloys (after Duwez6). 5.2. At. % T i . Figure 3_. Lattice parameters of alpha zirconium-titanium alloys (after Fast^ and Duwez"). - 7 - - 8 - monotectoid temperature. A short time after the diagram of Rogers and Atkins was incorporated g into th i s work, a s l ight ly different diagram was published by Bychkov et a l . The pr incipal difference contained i n their diagram was that the monotectoid occurred at 550°C. This difference was not supported by this research and so the diagram of Rogers and Atkins was s t i l l considered to be the best available. Rogers and Atkins also reported the l a t t i ce parameters for the region of complete beta sol id so lub i l i ty and this information is shown in Figure 5. The reaction rates i n this system are of reasonable speed. Alloys of less than 15 percent niobium undergo some transformation on quenching from 1100°C and, for those above 15 percent, the beta phase can be completely o retained to room temperature. The work of Finlayson outlined beta to mono- tectoid decomposition rates that were reasonably rapid, 4. The Titanium-Niobium Diagram. The titanium-niobium diagram determined by Hansen et a l ^ i s shown in Figure 6, The diagram exhibits a complete series of isomorphous so l id solutions across the beta f i e l d whereas niobium i s only s l ight ly soluble in the alpha titanium modification. The la t t i ce parameters for beta titanium-niobium alloys as reported by Hansen et a l are shown in Figure 7. The investigators found that with alloys containing more than 25 percent niobium residual coring could not be removed no matter how severely the alloys were cold worked and no matter how long they were homogenized. This was pr incipal ly due to the extremely sluggish reaction rates encountered and for this reason, the diagram was not accurately determined below 6506C. Such slow reactions do not affect this work materially as the titanium-niobium system is 3.6 At. f0 Nb Figure 5 The la t t ice parameters of beta zirconium-niobium alloys (after Rogers and Atkins7). - 10 - 26001 1 Figure 7 Lattice parameters for beta titanium-niobium alloys (after Hansen et a l ) . - l i - the minor side of the ternary diagram under consideration. II EXPERIMENTAL A, Alloy Preparation. The zirconium metal used in the alloys was iodide crystal bar supplied by the Foote Mineral Company. Table 2 gives the reported analysis of the bar from which a l l alloys were made. Table 2. Analysis of Crystal Bar Zirconium. Element Weight Percent Hf 2.17 S i 0.005 A l 0.002 Mn 0.001 Mg ' 0.002 Fe 0.002 Cr 0.001 ^ T i 0.006 Ni trace Ca 0.003 Cu 0.0005 o2 I i . 0.01 The titanium metal used was in the form of iodide crystal bar supplied by A.D. McKay Company. No specif ic analysis was available and so a typ ica l analysis i s quoted in Table 3. Table 3. Typical Analysis of Crystal Bar Ti tanium^ Element Weight Percent o2 0.01 N 2 0.005 C 0.03 Fe 0.04 Ca trace A l 0.05 S i 0.03 Pb trace Ni " trace Mo trace - 12 - The niobium metal used was i n the form of 4.7 mm. diameter rods supplied by Johnson, Matthey and Company. An exact spectrographic analysis of the rods supplied i s given i n Table 4. Table 4. Spectrographic Analysis of Niobium Rod. Element Weight Percent Ta 0.5 Ni 0.0007 Fe 0.004 T i 0.012 Melt stock was prepared by sawing s l ices from the respective metal bars. A small hole was d r i l l e d in each s l ice and then a l l were cleaned i n acetone. Each s l ice composing a ternary a l loy was then carefully weighed and f i n a l l y tied into a bundle u t i l i z i n g the small holes and 0.005 inch zirconium wire. The bundle was then cleaned a second time in acetone. A l l alloys were melted and cast by the levi ta t ion melting technique 12 previously described by Polonis et a l . Some changes were required for the satisfactory melting of zirconium al loys , the most significant being a s l i ght ly different c o i l than that used by Polonis for the melting of titanium al loys , 9 The c o i l design adopted was that used by Finlayson 7 and after proper alignment any a l loy desired up to 20 percent niobium could be melted with ease. The power supply used was a 23.5 Kva Lepel valve osc i l l a tor . A second departure from the or ig ina l practice established by Polonis was the use of purif ied helium instead of argon as the inert atmosphere and at a pressure of 15 psig instead of 5 psig to reduce power arcing from the c o i l to the specimen. The helium was purified by passing i t over activated charcoal at a pressure of 40 psig and at l iquid nitrogen temperature. The al loy bundle was suspended in the center of the levi tat ion c o i l by means of the 0.005 inch zirconium wire which was attached to a glass hook i n the top plate of the chamber. After evacuating the chamber and backf i l l ing with helium three times to the pressure mentioned, the power was quickly turned up to 100 percent output. When the specimen had melted and was judged to be sufficient- l y hot and thoroughly mixed, the power was slowly cut back, which effectively poured the molten al loy into the copper mold. A typica l ingot i s shown i n Figure 8. Figure 8. Typical levi tat ion melted-and-cast ingot. One check with an opt ica l pyrometer gave a temperature of 2500°C just prior to casting. At this temperature a black vapour was given off and was presumed to come from the molten zirconium and titanium as these two metals have f a i r l y high vapour pressures at such temperatures. A l l specimens so melted were bright and clean on removal from the mold. Weighing i n and out gave a difference of ±2 mg for a weigh-in of approximately 6.5 gms for each a l loy . In the absence of chemical analyses, - 14 - the weights of each element in an alloy must therefore represent the composition of each alloy. Table 5 l ists the ten alloys on which this research was based. A further seven alloys were rejected due to gas contamination either from melting or heat treatment. Table 5. Composition of Alloys Utilized. Alloy % Zr 3& T i % Nb T-8 90.0 5.3 4.7 T-9 85.4 10.3 4.3 T-10 79.0 16.4 4.6 T - l l 74.0 21.5 4.5 T-L2 64 .8 31.2 4.0 T-13 76.9 5.6 17.6 T -H 73.5 9.4 17.2 T-15 68.5 14.4 17.0 T-16 63.1 19.8 17.1 T-17 55.4 27.3 17.4 Slices were removed from the as-cast ingots for metallographic examination using a two-zero jeweler's hacksaw. The saw filings were collected for x-ray powder diffraction experiments. Iron from the saw blades was removed from a l l filings with a small magnet. B. Heat Treatments. The as-cast ingots were subjected to a constant, slight amount of compressive cold work to break up the as-cast structure. A l l ingots were wrapped in molybdenum sheet and placed in vitreosil bulbs containing zirconium getter chips. The bulbs were then evacuated and sealed off. Each bulb was heated to 1000 °C for 48 hours to promote homogenization and was then cooled at a rate of 100 °C per day until a temperature of 450 °C was reached. At t h i sJ temperature, the capules were held for a further 48 hours and then water quenched to preserve the structure at 450 ° C . The structures attained were . - 15 - considered to be the equilibrium ones for 4 5 0 ° C . Slices were taken from each ingot for metallographic examination and the saw f i l ings were collected as before. Sl ices from one low- and one high-niobium ingot were then given the heat treatments outlined i n Table 6. Table 6. Heat Treat Schedule for Two Al loys . 1 85.4% Zr-10.3% Ti-4.3% Nb 76.9% Zr-5.6% Ti-17.6% Nb 3 pieces 1 hr . at 900°C then 1 piece 24 600°C. and 1 piece £4 700°C and 1 piece 24 8 0 0 ° C . 3 pieces 1 hr. at 900°C then 1 pie.ce 70 525°C and 1 piece 70 600°C. and 1 piece 70 675°C. The tube furnaces used for the above l i s t treatments were a l l checked with a secondary standard platinum/platinum-10 perbent rhodium thermo- couple and a l l were found to control within ±5°C of the control point. j. Upon examining these specimens metallographically, i t was possible to outline the phase boundaries roughly. The saw f i l ings obtained from the homogenized and equilibrated-ingots were wrapped in molybdenum sheet and placed i n Pyrex bulbs along with zirconium. getter chips. The bulbs were then evacuated and sealed off . These bulbs were c next held at 450°C for 70 hours to strain relieve the saw f i l ing s without destroying the equilibrium structure. C, Met a l io graphy. A l l specimens examined were polished on number two through to number - 16 - four-zero emery papers. The specimens were preliminary lapped on waxed b i l l i a r d cloth using levigated 600x alundum.. F ina l lapping was done on micro-cloth using Linde B levigated alumina. Etching the specimens was somewhat d i f f i cu l t and a considerable amount of time arid effort was required before suitable etchants were devised (by t r i a l and error) to portray the structures adequately. In part icular , alloys exhibiting a monotectoid structure were very awkward to handle. Table 7 l i s t s the various etchants developed. Because of this d i f f i c u l t y , metallography has Table 7 Etchants for Zirconium-Titanium-Niobium Alloys . As-cast Structures Heat Treated Structures Chemical Polish No. 1 Etch No. 2 20 mis HN03 20 mis HNO3 30 mis l ac t i c acid 30 mis l ac t i c acid 10 drops HF 30 mis glycerine 6 drops HF Etch No. 1 20 mis HNO3 20 mis HF 60 mis glycerine been used only as a qualitative t o o l and x-ray techniques were depended upon to give quantitative results . D. X-Ray Technique. Lattice parameters and d-spacings were determined for a l l alloys equilibrated to 450°C by taking powder pictures of s tra in relieved saw f i l ing s obtained from heat treated ingots. A 114.6 mm. diameter Debye-Scherrer powder camera was used with the f i lm mounted i n the Straumanis posit ion. A nicke l f i l t e r was also incorporated inside the camera between the specimen and the - 17 - f i lm to reduce the strong fluorescent radiat ion. Copper Ka radiation was u t i l i zed with the tube operating at 40 Kv and 15 ma. Exposures of three hours were required to obtain satisfactory results . Lattice parameters for close-packed hexagonal crystal structures were calculated by the method of Cohen as indicated in Appendix B. Parameters for body-centered cubic phases were determined by extrapolating a plot of aQ versus Taylor-Sinclair function toQ = 9 0 ° . The quantitative results presented in th i s thesis are based on high- temperature x-ray goniometer plots . Butters and Parr^-3 had bui l t a high-tempera- ture attachment to f i t a Philips high-angle x-ray diffraction goniometer that re l ied upon an inert atmosphere to prevent specimen contamination. Their platinum furnace was wound on a v i t r e o s i l tube and this was believed to be the source of gas contamination that they encountered. To handle reactive zirconium al loy powders, i t was decided to redesign the high-temperature unit and u t i l i z e a high-vacuum system to prevent gas contamination. As much refractory material as possible was eliminated from the vacuum system. The furnace was wound from 0,010 inch zirconium wire with the wire strung longitudinally from molybdenum hooks which i n turn were insulated from the stainless steel end rings by small ceramic beads. Figure 9 shows the furnace with a zirconium radiation shield i n position and the external, water-cooled can. The zirconium winding and radiation shield provided a self-gettering action that improved the vacuum appreciably. The powder specimen was placed on a molybdenum specimen plate which i n turn was sprung onto a molybdenum rod harp. Provisions were made to a l ign the - 18 - Figure 9, High-temperature x-ray unit furnace with a zirconium radiation shield and the external, water-cooled can, harp accurately with the goniometer system. The platintlm/platinum - 10 percent rhodium thermocouple dipped into the powder on the specimen plate. Figure 10 Figure 10. Specimen plate arrangement for the high-temperature x-ray unit . - 19 - shows the specimen plate arrangement. A further innovation wa3 the use of 0.001 inch nickel f o i l window for the entry and exit of x-rays to the evacuated can. The ear l ier aluminum f o i l windows developed leaks after short use and were therefore not dependable. The nickel f o i l served both as a CuK^ radiation f i l t e r and a vacuum tight window. It was soft-soldered into position and can be seen in several of the photographs. Figures 11 and 12 show the experimental apparatus i n operation. VMF-10, air-cooled o i l diffusion pump and a Welch Duo-Seal 1/.00B backing pump. A pressure of 10"*̂  mm. of mercury was easi ly maintained at high temperatures. The vacuum pressure was measured with an NRC ion gauge. l imits of ±5°C were easi ly held. The thermocouple was calibrated by two independent methods. The f i r s t cal ibrat ion was accomplished by measuring the la t t ice parameter of Sherritt-Gordon hydrogen reduced copper powder with increasing temperature. The curve obtained in Figure 13 was then compared with the expression for the coefficient of thermal expansion for pure copper. The equation i s ; This calibration showed the thermocouple to be without error. However, the expression above demands an accuracy which was not attained i n the l a t t i ce parameter measurements u t i l i z e d and an error of 10°C would l i k e l y not be noticeable. The vacuum pumping system consisted of a l i qu id nitrogen trap, a The temperature was controlled d irect ly by means of the Variac and The second calibration eliminated this uncertainty as a material exhibiting a transformation was u t i l i z e d . Pure crystal l ine quartz was suitable Figure 12. View of high-temperature x-ray unit showing the Geiger-counter scaler, rate meter and recorder. 7.00 3.62| I i | I I I I I i 0 200 400 600 800 1000 Degrees Centigrade (indicated) Figure 13. Lattice parameter versus temperature f o r hydrogen reduced copper powder as measured i n the high- temperature x-ray uni t . - 22 - as i t has a sharp la t t ice expansion at 5 7 3 ° C . Accordingly, the d-spacings for one plane of a s i l i c a specimen versus temperature were obtained and the result ing curve is shown in Figure 1 4 . A hysteresis of 10°C was encountered and as the cooling and heating rates were roughly equal, the true transformation temperature was taken to be the average, which gave a true temperature of 5 8 5 ° C . The thermo- couple was thus in error by +12°C and this error was subsequently subtracted from the indicated temperatures u t i l i zed for the determination of the ternary isopleths. III RESULTS A. Metallographic Data Figures 15, 16, 17 and 18 show photomicrographs that were completely typ ica l of a l l specimens. Two groups were apparent; low niobium alloys had equivalent structures and high niobium alloys had equivalent structures for any given heat treatments. 9 The needle-like markings in the as-cast specimens remain unidentifxed, but are suspected to be hydrides. No extra lines were 'visible i n x i r a y powder pictures of the as-cast powders. Further information on their nature must await micro-beam x-ray experiments being conducted at Chalk River. Figures 19, 20, 21 and 22 are photomicrographs of the sl ices used to outline the ternary phase boundaries roughly. Figure 20 demonstrates that the 3/ct + P boundary must l i e below 7 0 0 ° C . Figure 22 demonstrates that the P/cx + BNb boundary must l i e below 6 0 0 ° C . This was the extent of the metallo- graphic work and i t w i l l be shown that the x-ray results compare favourably with these data. 1.86 6 1 0 0 2 0 0 " 3 0 0 4 0 0 ! 5 0 0 5 0 0 7 0 0 Degrees Centigrade (indicated) Figure 14. d-spacings of one plane versus temperature for pure s i l i c a as measured in the high temperature x-ray unit . Figure 15 85.4$ Zr-10.3$ Ti-4.3% Nb Figure 16 Same equilibrated to as-cast. Transformed p, 450 °C . a . i . e . , a » . Chemical polish Etch No. 2 x 800. No. 1. Etch No. l x 800 Figure 17 76.9$ Zr-5.6$ Ti.-17.6jt Nb as*-cast. Retained p + unidentified needles. Chemical polish No. 1. Etch No. 1 x 800. Figure 18 Same equilibrated to 4 5 0 ° C . Monotectoid a + pNb. Etch No. 2 x 800. - 25 - Figure 19 85.4% Zr-10.3% Ti-4.3% Nb held at 600°C f o r 24 hours af t e r 1 hour at 900°C. a. Etch No. 2 x 800 Figure 20 Same held at 700°C f o r 24 hrs. after 1 hr. at 900°C. Transformed P. Etch No. 2 x 800. Figure 21 76.9% Zr-5.6% Ti-17.6% Nb held at 525°C for 70 hrs. after 1 hr. at 900°C. a + 0Nb. Etch No. 2 x 800 Figure 22 Same held at 600°C f o r 70 hrs. aft«r 1 hr. at 900°C. Retained p + needles. Etch No. 2 x 800. - 26 - Figure 23 i s a photomicrograph of powder taken from the high- temperature x-ray u n i t . The powder was heated to 900°C and then was being cooled at the rate of 100°C per hour i n an attempt to observe the p/a + p Figure 23. 64.8% Zr-31.2% Ti-4.0% Nb powder from the high-temperature x-ray unit, a + retained P + x. Etch No.2 x2500 phase change. Unexpectedly an unidentified phase began to precipitate, and the experiment was terminated by a rapid cooling to room temperature. An x-ray powder picture showed three phases to be present; a, retained 3, and the unidentified phase. The photomicrograph was included to point out the d i f f i c u l t i e s encountered when v i s u a l i d e n t i f i c a t i o n was attempted. B. Lattice Parameters The d-spacings for a l l a-containing alloys equilibrated to 450°C are given i n Appendix C and are compared to the National Bureau of Standards d-spacings for pure zirconium. Included also i n Appendix C i s a table of d- spacings for the unidentified phase mentioned above and i t s tentative i d e n t i - f i c a t i o n . Nearly a l l powder films contained some f a i n t extra l i n e s that could not be indexed. - 27 - Figures 24 and 25 show the variation of c and a for increasing atomic percent titanium. The 64.8$ Zr-31.2$ Ti-4.0$ Nb al loy parameters were not plotted in Figure 24 as i t s structure was nearly 100. percent 3 at the temperature considered with some weak a phase l ines . This w i l l also be shown i n the ternary isopleth determined for the 4.5 percent niobium al loys . The 55.4$ Zr-27.3$ T i - 17.4$ Nb al loy parameters were not plotted in Figure 25 for the same reason. Figures 26 and 27 show the la t t ice parameters for the 3 ^ phase of the monotectoid. If Vegard's law i s obeyed for the ternary system, then i t can be shown that the 3 N b parameter for the 64.8$ Zr-31.2$ Ti-4.0$ Nb al loy i s equal to the parameter predicted by Vegard's law for the region of 3 so l id so lub i l i ty . The same i s nearly true for the 55.4$ Zr-27.3$ Ti-17.4$ Nb a l loy . C. Ternary Isopleths The term ' i sopleth ' denotes a ternary ver t i ca l section that either originates in one corner of the ternary triangle and thus has a constant ratio of second to th i rd components or is para l l e l to one side of the ternary triangle and thus has one component constant. The two ternary isopleths presented in Figures 28 and 29 were constructed entirely from data obtained from the high-temperature x-ray unit . The isopleth in Figure 28 has a constant niobium content of approximately 4.5 percent. The one in Figure 29 has a constant niobium content of approximately 17.5 percent.-. Both isopleths were constructed by heating and cooling al loy powders in the high-temperature x-ray unit and observing the growth and decomposition of the various phases present. The low niobium isopleth consists of 3 decomposing to a + 3 which decomposed in turn to a + 3^. The exact temperatures of the phase boundaries presented were obtained by plott ing peak intensities versus temperature and extrapolating to zero peak intensity. - 28 - c •H o cd 3.30 3.25 - 3.15 5.15 - 5.10 0<jj C •H O O -5.05 3.5 Balance Zr 5.00 40 A t . * T i At.% Nb Figure- 2 4 . Variation of c and a for a phase in monotectoid alloys of low niobium content at 4 5 0 ° C . Figure 2 $ . Variation of c and a for a phase i n monotectoid alloys of high niobium content at 4 5 0 ° C . - 29 - 3.50 Figure 26. Variation of a 0 for P^b phase in monotectoid alloys of low niobium content at 4 5 0 ° C . 3.50 Figure 27. Variation of aQ for P^b Phase in monotectoid alloys of high niobium content at 4 5 0 ° C . - 30 - .900 0 15 % T i 30 Nb constant at 4.5% Balance Zr Figure 28. Ternary isopleth with niobium constant at 4.5 percent (temperatures corrected). . Figure 2 9 . Ternary isopleth with niobium constant at 17.5 percent (temperatures corrected) - 31 - Appendix D contains the information obtained for one a l l o y . Sample scans of the type of reaction occurring i n alloys of low niobium content are shown i n Figure 30. Held at 468*C for 10 mins Held at 683'C for 10 mint. Held at 903*C tor 10 mint. o c ^ , ° ' oc,o.^ A Jo "A pr n * 37* ' ' 3W> 1 1 37* ' 36* ' 35* L"3> ' 36» 1st Scan 2nd Scan 3rd Scan Diffractometer plots of 85.4% Z r -10 .3% Ti~ 4.3% Nb showing the transformation of oc -> oc + ^ -> $ Figure 30 Sample scans showing the transformation of a to 3 . The high niobium isopleth i n Figure 29 was determined i n much the same manner except that much longer times at temperature were required to make the reactions go to any extent. Figure 31 shows sample scans and a l l indicate that hysteresis was not too serious. Both isopleths were constructed with corrected temperatures, that i s , the error suggested by the s i l i c a powder temperature standardization run had been compensated for by subtracting 12°C from each experimentally determined temperature. Figure 32 shows the growth of the unidentified phase mentioned e a r l i e r . The scans shown are those res u l t i n g from a direct experiment to determine the structure of the extra phase. When the phase was developed as much as possible, the specimen was rapidly cooled to room temperature and then an x-ray powder d i f f r a c t i o n picture was taken. The phase was then ten t a t i v e l y i d e n t i f i e d as Mtld at 583* C tor 23 hour* $ I I O ' O C I O I I st Scan 2 nd Scan Held a l 5 8 3 * C for I hour P 110 • a. 101 - H e l d 01 5 8 3 * C tor tt hours • oc lOt § N b l l O Ot 002 9 N» 1,0 OC 002 3? ' 36* 1 3 rd Scan 4 th Scan Diffractometer plots of 73.5%Zr- 9.4%Ti-l7.2%Nb showing the monotectoid transformation. Angles are 26 degrees. Temperatures are not corrected. Figure 31. Sample scans showing the monotectoid transformation. Held at 637*C tor lOmins Held at 5 7 5 »C tor 10 mins Held at 480"C for K> tains. i t i / « « • » p . NO (3 HO CJ 002 j \»- 8 j W 002 QC lot 8 110 , i '• U> 002 5*7̂  ' 36" ' 38-! ' 37- ' 36°~ 1st Scan 2nd Scan 3rd Scan Diffractometer plots of 64.8% Zr-31.2% Ti-4.0%Nb showing the growth of the transition co phase. Angles are 2 6 degree*. Temperatures are not corrected. Figure 32. Sample scans showing the growth of the t r a n s i t i o n Co - phase. - 33 - being tetragonal with a 0 = 3.85 A, c 0 = 4.83 and c/a = i . 2 5 D» Ternary Isothernials. U t i l i z i n g the ternary isopleths determined experimentally and the zirconium-niobium binary with the zirconium-titanium binary, a series of ternary isothermal sections f o r the zirconium-rich corner of the system can be approxi- mated. The deficiencies of isothermal sections w i l l be discussed i n Section IV. Figures 33(a) to (h) are the isothermal sections and portray the ternary diagram from 800°C to 450°C inclusive i n 50°C steps. • . • • i IV DISCUSSION OF RESULTS AND CONCLUSIONS No previous work could be found that would be useful as a guide i n the interpretation of the results presented. However, a textbook by R h i n e s ^ was very useful i n sketching the isothermal sections i n that i t portrayed the shapes possible and pointed out impossible thermodynamic e q u i l i b r i a . Rhines also stated that very l i t t l e was known about the mechanism and reaction rates of ternary eutectoid reactions. However, the analogy between binary eutectic- binary eutectoid and ternary eutectic-ternary eutectoid reactions appears to be good i n a l l respects. The p r i n c i p a l source of u n r e l i a b i l i t y i n the results presented i s the unknown l e v e l of contamination i n the a l l o y s . No gas analyses were obtained on 15 the as-cast ingots and the heat-treated powders. One reference to gas contamination i n the drip-melting of zirconium stated that within the accuracy of a n a l y t i c a l methods, neither oxygen (200 ppm) nor nitrogen (5 ppm) was picked L up when the metal was melted i n a vacuum of 10 mm of mercury. As the high- temperature x-ray unit was operated at an equally good vacuum, i t i s f e l t that 50 % T i 40, V V V B + 3Nb Zr 10 20 fo Nb 30 40 Figure 33(a) Isothermal section at 8 0 0 ° C . 50 - 35 - Figure 33(b) Isothermal section at 750°C. Figure 33(c) Isothermal section at 700°C. Figure 33(d) Isothermal section at 6 5 0 ° C . - 38 - - 39 - Figure 33(f) Isothermal section at 550°G. - uo - Figure 3 3 ( g ) Isothermal section at 5 0 0 ° C . % Nb Figure 33(h) Isothermal section at 4 5 0 ° C . - 42 - gas contamination in the unit was not serious. Nevertheless, the relative gettering a b i l i t y of powdered zirconium and molten zirconium i s unknown and in addition, the powder was exposed to the vacuum at medium temperatures for some time (up to 24 hours) whereas the molten zirconium was in the active state for a matter of only one or two seconds. Gas analyses alone can settle the problem. It should be noted that two points on the low niobium ternary isopleth are questioned. It is f e l t that these points were unreliable due to gas contamination. They were included to show the effect of contamination on the transformation temperatures. The usefulness of the la t t ice parameters measured appears to be low and this is especially true of those obtained for the close-packed hexagonal phases. F i r s t l y , in no x-ray pattern were the high-angle a-doublets resolved, as is considered necessary for accurate measurements. Secondly, Vegard's law does not appear to be obeyed, especially in the high niobium a l loys . . Thirdly, higher accuracies than were attained are required as differences i n the fourth significant figure of the c/a ratio are important. The 3Nb la t t ice parameters are considered to be good, for plots of the Taylor-Sinclair function versus l a t t i ce parameter show l i t t l e random and systematic error. The la t t ice parameter plots correlate very nicely with the determined isopleths as the parameters exhibit a change i n l inear i ty when they cross a phase boundary exhibited in the isopleths. None of the plots of la t t ice parameters were of use in determining the isothermal section at 450°C as many more alloys would be required to construct accurate t i e lines of isoparameters. - 43 - Further, the compositions of the precipitated phases i n the mono- tectoid reaction were unknown and so their positions could not be located. F ina l ly , B r i l l o u i n zone e f f e c t s , ^ largely qualitative for alpha zirconium, may al ter the c/a ratio as the amount of zone overlap changes. This would be sufficient to upset Vegard's law. The metallographic results are too sparse to warrant much discussion. Chiefly, the data obtained correlate^ f a i r l y well with the measured isopleths and thus suggest that the high-temperature powder technique is quantitatively useful for reactive metals. The high-temperature x-ray unit fa i led in one respect in that no clear indication was obtained that a three-phase f i e l d (iix + P + Pjnj) existed under the monotectoid reaction plane. Such a f i e l d was not shown on the high niobium isopleth, but has been dotted i n on the isothermal sections as an estimate to keep experimentally undetermined areas quite general. The ternary isopleths as presented are f e l t to be quite accurate, although temperature l imits of ±10°G must be placed on the points because of unavoidable hysteresis effects. It should be emphasized that the isopleths do not represent equilibrium conditions i n the sense that a binary diagram does. Tie l ines in two phase areas joining points i n equilibrium w i l l l i e in the plane of any given isopleth only by coincidence and then rarely. This is one of the conditions that a true quasi- binary must f u l f i l l , and such is certainly not the case for the isopleths presented i n this work. One interesting phenomenon observed during operation of the high- temperature unit was the development of a metastable transit ion phase i n two - kU - high-titanium, low niobium al loys . The phase was eventually identi f ied as being tetragonal and was called an co-phase after the titanium notation already i n force. Such a transit ion phase has been observed in several titanium systems, '17 principal ly the titanium-vanadium system ' where reversion and retrogression 18 phenomena were also noted. Domagala et a l make the f i r s t reference to any such transit ion phase occurring in zirconium-rich.alloys. Perhaps such a transit ion phase would account for the unexplained extra l ines observed by 7 10 ' Rogers and Atkins and Hansen et a l in their constitutional diagram work. In this research, the so-called (O-phase was found to be reversible and, i t s formation could be suppressed i f a suf f ic ient ly low cooling rate were used. As the data being collected were to be based on equilibrium structures, any further <*> formation was suppressed when encountered. However, some bel ief that i t arises because of contamination exists and i t s true nature should therefore be more f u l l y explored. The isothermal sections constructed from the isopleths and the zirconium binaries are only of a qualitative nature. The true nature of the J+50°C isothermal section i s somewhat obscure and many more alloys would be required to outline the region of intermediate titanium content more accurately. In conclusion, two isopleths have been determined for the zirconium- r i c h corner of the zirconium-titanium-niobium constitutional diagram. Lattice parameters for both phases of several monotectoid alloys at U50°C have also been measured but they were of limited usefulness due to a general lack of data in other regions of the ternary diagram. A high-temperature x-ray unit was designed which handled reactive zirconium al loy powders quite wel l up to temperatures of 1 1 0 0 ° C . However, much more experimental work would be - 45 - required before the ternary diagram could be accurately outlined and time- consuming techniques would be required. V. RECOMMENDATIONS FOR FURTHER WORK Further work on this ternary system must f i r s t check the results presented. It i s f e l t that dilatometric studies would be very valuable though d i f f i cu l t to carry out. The resistometric technique described by Rogers and Atkins? and modified by Finlayson' would also give much information. Many more alloys would be required for a complete study of the zirconium corner and a knowledge of the contamination level would be essential for accurate work. APPENDIX A Related Binaries of Impurity Elements 2100 Zr 10 20 30 40 At. fo Oxygen Zirconium-oxygen system (after Hansen et al l9) APPENDIX A (continued) L / L + ZrN / % Nitrogen Zirconium-nitrogen system (after Domagala and McPherson* 0). Zr 50 60 At. % Hydrogen '" Zirconium-hydrogen system (after Edwards et al 2^-). 70 APPENDIX A (continued) 2000 1800 r- 1600 r- U00 h ieoo r- 1000 h 800 20 30 At. % Oxygen Titanium Oxygen System (after Bumps et al^2). APPENDIX A (continued) 2600 T i 10 20 30 40 At. fo Nitrogen Titanium-nitrogen system (after Palty et al 2 ^) APPENDIX A (continued) 1000 T i 20 40 60 80 At. % Hydrogen Titanium-hydrogen system (a composite of several researches) APPENDIX B - 52 - Lattice Parameter Calculation by the Method of Cohen Cohen's method of determining la t t ice parameters i s of most use when applied to noncubic substances, since straight forward graphical extrapolation cannot be used when there i s more than one la t t ice parameter involved. Cohen's method provides a direct means of determining these parameters. For. a hexagonal substance, « 2. o s i n 2 Q (true) = Jv . £ . h 2 + hk + k 2 + A . j 2 4 3 " IrT- 4 C 2 2 2 2 and s i n 2 & - A (h 2 + kk + k 2 ) - /\ (I ) - D s i n 2 & 3a02 4c02 i f the pattern is made in a Debye-Scherrer camera. By rearranging the equation and introducing new symbols, we obtain s i n 2 6 <* Ca +' By + AS 2 2 where C = X , a = (h 2 + hk + k 2 ) , B = A , 2 y =£ , A = D_ and 8 = 10 s in 22© 10 The values of C, B and A , of which only C and B are needed, are then found from the three normal equations: £ a s i n 2 © » C £ . a 2 + B£ay + A£aS £y s i n 2 © = C^ay + Bgy2 + A£y8 £ 8 s i n 2 0 » C £ a S + B^Sy + A £ S 2 .rc: : i k F o r „ t h i s worki ,four.high-angle ' l ines were chosen-:(ie. the 213,3Q2,A 205. «hd'106 pl^eslJf^a^SMSi^feSfr'three normal equations. The a *s and c ' s were then solved for . - 53 - APPENDIX C d-Spacings of the a-Containing Alloys and the t>J• -Phase A l l equilibrated to 450°C. .5.3%"Ti 10.3%'Ti - 16 .4%-Ti '21.5%'Ti Index NBS .4.7% Nb 4.3% Nb 4.6% Nb 4.5% Nb 100 a 3̂ 2; o 798 .2.762 2.749 2.743 2.725 extra 2.677 2.662 002 a 2.573 2.538 2.517 2.584 2.503 101 a 2.459 2.425 2.415 2.409 2.394 HO 3Nb 2.328 2.328 2.394 102 a 1.894 I.873 I.865 1.860 2.394 003 a 1.692 200 p N b 1.650 1.700 110 a 1.616 1.599 1.590 1.585 1.579 103 a 1.463 1.448 ' 1.441 1.435 1.425 200 a 1.399 1.384 1.377 1.378 1.367 211 3Nb 1.388 112 a" 1.368 1.355 1.348 1.346 1.336 201 a 1.350 1.338 1.331 1.327 1.320 004 a 1.287 1.275 1,268 1.261 1.252 202 a 1.230 1.219 1.211 1.208 1.203 104 a 1.169 1.160 1.150 1.146 1.142 203 a 1.084 1.077 1.069 1.066 1.059 210 a 1.059 1.049 I.O46 1.041 1.034 310 3Nb 1.077 211 a 1.036 1.029 1.022 1.018 1.014 114 a 1.006 1.000 .994 .988 .983 extra .986 .973 212 a .978 .971 .965 .960 .958 105 a .966 .959 .953 .947 .943 204 a .947 .934 .935 .925 .930 300 a .933 .927 .921 .916 .910 301 a .905 213 a .900 .894 .889 .885 .881 302 a .877 .871 .866 .862 .859 006 a .858 ..851 .844 .845 205 a .829 .824 .818 .814 .811 106 a .820 .814 ' .807 .804 220 a .803 .799 .794 APPENDIX C (continued) M l equilibrated to 450°C. 5.6% T i 9.4% T i 14.4% T i 19.8% T i 27.3%' T i Index NBS 17.6% Nb 17.2% Nb 17.0% Nb 17.1% Nb 17.4% Nb 100 a 2.798 2.769 2.768 2.754 2.744 2.731 extra 2.688 2.687 .2.685 2.670 2.660 002 a 2.573 2.540 2.539 2.531 2.522 2.512 101 a 2.459 2.434 2.429 2.419 2.409 2.399 no PNb 2.330 2.329 2.325 2.339 2.373 102 a 1.894 1.878 1.870 1.869 1.858 1.855 extra 1.741 200 3Nb 1.652 1.649 1.649 1.656 1.683 110 a 1.616 1.606 1.600 1.593 ( 1.588 1.584 extra 1.524 103 a 1.463 1.452 1.450 1.492 V 1.437 1.432 extra 1.446 200 a 1.399 1.389 1.381 1.381 • 1.375 1.375 112 a 1.368 1.361 1.355 1.352 i . 1.348 1.343 201 a 1.350 1.340 1.337 1.334 1.328 1.324 extra 1.304 1.301 1.298 004 a 1.287 1.278 1.273 1.272 1.264 1.263 extra 1.263 202 a 1.230 1.221 1.219 1.214 1.208 1.206 220 pNb 1.172 1.172 1.169 1.173 1.191 104 a 1.169 1.162 1.159 1.154 1.147 203 a 1.084 1.077 1.075 1.072 1.067 210 a 1.059 1.051 1.047 1.045 1.049 1.042. 310 PNt 1.045 1.047 1.045 1.049 1.066 211 a 1.036 1.029 1.028 1.024 1.020 1.018 extra 1.003 114 a 1.006 1.001 .999 .995 .991 .987 extra .975 212 a .978 .973 , .970 .968 .964 .975 105 a .966 .960 .958 .954 .951 .946 204 a .947 .941 .939 .938 .932 .928 300 a .933 .928 .926 .924 .919 321 PNb .885 .885 .883 .887 .902 213 a . .900 .896 .893 .890 .887 .886 302 a .877 .873 .870 .867 .864 .861 006 a .858 .854 .851 .845 .842 .842 400 pNb .829 205 a .829 .825 .823 .819 .816 .816 106 a .820 .819 .811 .808 .805 .803 220 a .804 .802 .799 .796 .795 APPENDIX C (continued) Cj — Phase d - Spacings Zi"-Mo 18 After Domalaga et a l Ti-V 17 After Brotyen et a l ' 31.2%. .4.0%; Nb 3.154 2.74 3.041 2.309 2.28 2.453 2.204 1.626 1.909 1.967 1.398 1.734 1.908 1.317 1.519 1.636 1.202 1.410 1.571 1.151 1.288 1.335 .967 1.218 1.166 .915 1.094 1.068 .894 1.031 1.030 .871 .995 0.982 .850 .951 0.877 .799 .921 0.813 .857 .812 - 56 - APPENDIX D Temperature Determination of Phase Boundaries i n One Low Niobium Alloy. •(74.0$ Zr - 21.5$ T i - 4.5$ Nb) 700 \ 8 650°C o a heating • a cooling c ±20 °C O 3 heating 0 3 • cooling • a + 3 • 455°C X 1 1 ±15°C 1 1 1 500 400 20 40 ^0 80 100 120 Peak Areas i n Absolute Units as Measured with a K. and E. Polar Planimeter. - 57 - BIBLIOGRAPHY 1. B.D, C u l l i t y , 'Elements of X=Ray D i f f r a c t i o n ' , Appendix 13, Addison-Wesley Publishing Company, Inc. (1956). 2. P.C.L. P f e i l j A Discussion of the Factors Affecting the Constitution of Zirconium A l l o y s , Report AERE-M/R-960, June 2 7 , 1952. 3 . P.C.L. P f e i l , A C r i t i c a l Review of the Alloying Behaviour of Zirconium, Report AERE-M/TM-11, June 9, 1952. 4. J.D. Fast, The Transition Point Diagram of the Zirconium-Titanium System, Rec, Trav. Chim., 58s973, (1939). 5. E.T. Hayes, A.H. Roberson and O.G. Paasche, Zirconium-Titanium System: Constitutional Diagram and Properties, Bur. Mines Dept. Invest. 4826, November, 1951. 6. P. Duwez, A l l o t r o p i c Transformation i n Titanium-Zirconium Alloys, J. Inst. Metals, 80:525, (1952). 7. B.A, Rogers and D.F.Atkins, Zirconium-ColumbiUm Diagram, Trans. Ail.M.E., 203:1034, (1955). 8. Yu F. Bychkov, A.N. Rozanov and D.M. Skorov, Atomnaya Energia, 2:146, (1955). 9. M.J. Finlayson, "Isothermal Transformations i n Eutectoid Zirconium-Niobium Alloys', M.A.Sc. the s i s , University of B r i t i s h Columbia, (1957). 10. M. Hansen, E.L. Kamen, H.D. Kessler and D.J. McPherson, Systems Titanium- Molybdenum and Titanium-Columbium, Trans. A.I.M.E., 191:881, (1951). 11. M.K. McQuillan and A.D, McQuillan, 'Titanium', Chapt.10, 335, Butterworths S c i e n t i f i c Publications, (1956). 12. D.H. Polonis, R.G. Butters and J.G. Parr, Research, 7.:No. 2, (1954). 13. R.G.Butters and J . Gordon Parr, Canadian Journal of Technology, 33:117, (1955). 14. P.N. Rhines, 'Phase Diagrams i n Metallurgy', McGraw-Hill Book Company, Inc., (1956). 15. B. Lustman and F. Kerze, J r . , Editors, "The Metallurgy of Zirconium', Chapt.6, 2 4 7 , McGraw-Hill Book Company, Inc., (1955). 16. .Bi Lustman and F. • Kerze/>» ,:i;Edi^tors, 'The Metallurgy, of Zirconium', Chapt.9, 433, McGraw-Hill Book Company, Inc., (1955). 17. F.R. Brotyen, E.L. Harmon, J r . and A.R. Troiano, Decomposition of Beta Titanium, Trans, A.I.M.E., 203 : 4 1 3 , (1955). 18. R.F, Domagala, D.W, Levinson and D.J. McPherson, Transformation Kinetics and Mechanical Properties of Zr-Mo Alloys, 209:1191, (1957). - 58 - Bibliography (continued) 19. M. Hansen, D.J. McPherson and R.F. Domagala, Phase Diagrams, of Zirconium- base Binary Alloys, Report GOO-123, (1953). 20. R.F. Domagala dn D.J. McPherson, Armour Research Foundation, Project B017, Report 147"(1954). 21. R.K. Edwards, P. Levesque and D. C u b i c c i o t t i , 111. Inst, of Tech., ONR Project 358-070, Report 13, (1953). 22. E.S. Bumps, H.D. Kessler and M. Hansen, Trans. A.S.M., £5:1008, (1953). 23. A.E. Palty, H. Margolin and J.P. Nielsen, Trans. A.S.M., .46:312 (1954).


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