Processing of CuZr Based Shape Memory Alloys

Abstract

In the present work an investigation on primary processing of CuZr based shape memory alloys is proposed. In particular, the study addresses the effect of hot rolling process on the properties of CuZr shape memory alloys, in which the addition of some elements, such as Cr, Co and Ni, is taken into account. These alloys are produced by means of vacuum arc melting furnace under non contaminating conditions. Considering the high reactivity of these alloys, due to Zr element, hot working was undertaken after sealing the ingot cigars in a stainless steel protective can. The characterization of the rolled alloys is performed using DSC in terms of evolution of martensitic transfor-mation temperatures. The analysis is completed with mechanical and the microstructure investigations by means of microhardness and scanning electron microscopy (SEM) observations, respectively. The main result of this work is the evaluation of hot workability property of this system, which can be improved by adding metallic elements to the binary CuZr intermetallic system. Moreover, interesting characteristics, such as high transformation temperatures, thermal stability and reduced thermal hysteresis, can be also improved by means of the addition of Ni and Co at the same time.