Relaxation in shape-memory alloys—Part II. Thermo-mechanical model and proposed experiments

Abstract

A variety of relaxation phenomena such as stabilization of martensite, rubber-like behavior, evolving hysteresis loops and stabilization of interfaces have been observed in various shape-memory alloys. These effects adversely impact technological applications. In Part I of this paper we proposed a phenomenological, but predictive, model of the mechanical behavior of these materials. We showed that this model reproduces the experimental observations. In this part, we extend this model to include the effects of temperature and the austenite-martensite transformation. Once again, the predictions from this extended model agree with experimental observations. We can therefore conclude that the basic phenomenological ideas combined with a few easily measured material parameters is sufficient to predict the behavior of these materials. Finally, we propose new experiments in order to probe longstanding issues concerning the mechanism responsible for the relaxation.