Influence of Cold Working on Deformation Behavior and Shape Memory Effect of Ti-Ni-Nb

Abstract

Thermo-mechanical characteristic of shape memory alloy depends on cold working and heat treatment, because these processes can control the amount of defects including dislocation and precipitation [1]. In this study, the influence of cold working on the deformation behavior and the transformation characteristics was investigated on the Ti-Ni-Nb shape memory alloy (SMA). Both the tensile test and the shape recovery test were performed for the wire specimens of 1mm in the diameter with some different rates of cold working. The shape recovery tests were performed for the wire specimens of different cold working rates until the various levels of maximum applied strain, and the reverse-transformation characteristics on the process of heating after unloading were studied. It is clarified that the higher cold-working rate improves the shape memory properties of the alloy.