Effect of Cu addition on microstructure and mechanical properties of NiTi based shape memory alloy

Abstract

In this research paper, pre-alloyed NiTi based shape memory alloy and 4%Cu were used as starting powder materials. Starting powder materials were blended for 60 minutes by a turbula mixer. After mix processing, microstructure and phase transformations of powders were characterized using X-ray (XRD), elemental distribution spectrometry (EDS), scanning electron microscopy (SEM). Prepared powder mixtures as NiTi and NiTi+4%Cu alloys were pressed at 785MPa in a mold and then sintering process was applied to materials at different temperatures and time. Formation of multiphase’s (Ni3Ti, NiTi, Ti2Ni, Ni4Ti3 and NiTiCu) and positive effects of Cu addition were obtained by sintering at different temperatures and time. And also, stabilized NiTi phase and increasing the value of micro hardness were determined with added 4%Cu powders.