UBC Theses and Dissertations
Pseudoelasticity and the strain memory effect in Cu-Zn-Sn Eisenwasser, Jacob David
An investigation of pseudoelasticity and the strain memory effect was carried out on the β’-bcc phase of alloy of composition Cu-33Zn-3.4Sn. Pseudoelasticity was found to occur by a stress-induced, martensite transformation. Maximum pseudoelasticity occurred at the Af temperature and was ~8% for single crystal specimens and ~4% for polycrystalline specimens. Calculations indicated that the large strains were due to a transformation from a bcc to a fct martensite structure. The strain memory effect was studied by deforming specimens below Af and then heating above Af. At temperatures between Ms and Af, the deformation is accommodated by the stress-induced martensite formation. At temperatures below Mf, deformation of the martensite takes place and it is suggested that there is a change in the martensite structure with an increase in the amount of orthorhombic martensite present. The pseudoelastic and strain memory effects have very similar origins and over a wide temperature range from well below Mf to well above As the combined pseudoelastic and strain memory recovery is essentially 100%.
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