The Influence of Thermal History on the Pseudoelasticity of Copperzinc Based Alloys and the Mechanical Behaviour of Martensite

Abstract

Alloys exhibiting shape memory and pseudoelastic behaviours have many potential applications. A common feature amongst these alloys is that they all undergo a martensitic transformation either on cooling or under an applied stress. The alloys are thus characterized by certain parameters as M_s, the martensite transformation temperature on cooling, and σ ^P−M_T , the critical stress needed for the transformation above M_s. The choice of the alloy depending on the specifics of use and the conditions of application are therefore dependent to a very large extent on the above mentioned parameters. The constancy of these parameters in a material under the influence of temperature and stresses during use is essential. Any changes otherwise would seriously alter the shape memory and/or the pseudoelastic recovery properties of the alloy and thereby affect the lifetime of the part or parts being used.