Effect of Aging Treatment On Superelastic Behavior of Ti-50.3at%Ni Alloy

The yield stress of general metals represents the critical stress for slip. However, since the yield stress of superelastic alloys represents either the critical stress for slip or the critical stress for inducing martensite, it is difficult to determine the critical stress for slip and the critical stress for inducing martensite of superelastic alloys. Also, superelastic behavior of superelastic alloys is affected by environment temperature, aging temperature and aging time. In the present work, tensile loading-unloading tests have been carried out on the aged Ti-50.3at%Ni alloy at temperatures above reverse transformation finish temperature, and the critical stress for slip and the critical stress for inducing martensite have been obtained from the maximum applied stress-plastic strain relation and the maximum applied stress-recovery strain relation, respectively. The present work discusses effects of environment temperature, aging temperature and aging time on the critical stress for slip and the critical stress for inducing martensite.