Deformation Behavior of Ti-4Au-5Cr-8Zr Superelastic Alloy With or Without Containing Ti3Au Precipitates☆

Abstract Ti-Au-Cr-Zr alloys have been developed as novel Ni-free shape memory and superelastic alloys. In this study, the effect of heat treatment temperature on the precipitation behavior of Ti 3 Au and superelasticity of Ti-4Au-5Cr-8Zr (mol %) alloy was investigated by θ -2 θ X-ray diffraction measurement (XRD), scanning electron microscopy (SEM) observation and tensile tests. Ti 3 Au precipitates were formed homogenously in β (bcc) matrix in the specimen heat-treated at 1073 K, whereas only β phase was observed in the specimen heat-treated at 1173 K. Although both the specimens with or without containing Ti 3 Au precipitates exhibited superelasticity at room temperature, better superelasticity was observed when Ti 3 Au precipitates were formed by the heat treatment at 1073 K. Based on the evaluation of residual plastic strains after applying a constant maximum stress of 370 MPa at room temperature, the precipitation of Ti 3 Au formed at 1073 K was effective to reduce plastic deformation, resulting in good room temperature superelasticity in Ti-4Au-5Cr-8Zr alloy with containing Ti 3 Au precipitates.