Compositional dependence of crystalline structure, martensitic transformation temperature and vickers hardness of zr-cu system alloy

Zr-Cu shape memory alloys have considerable promise as a high temperature shape memory alloy. Shape memory behavior of the alloy is induced by the effect of martensitic and reverse martensitic transformation behavior of the intermetallic compound ZrCu. Previous reports suggest that additional elements such as Al, Cr, Co and Ni, etc. are effective to control martensitic transformation temperature of Zr-Cu system shape memory alloys. The objective of the present study is to investigate the compositional dependence of crystalline structure, martensitic transformation temperature and mechanical property of Zr-Cu system shape memory alloy. Near equi-Atomic Zr-Cu binary and equiatomic Zr-Cu system ternary alloys were fabricated by arc melting method with different alloy compositions. Especially, in the present study, Al was used as the third additional elements. The crystalline structures, martensitic transformation temperatures and hardness of fabricated alloys were investigated by means of X-ray diffraction(XRD), differential scanning calorimetry(DSC) and Vickers hardness test. As the results, it was found that the intermetallic compound ZrCu martensite phase was formed in both Zr-Cu binary and Zr-Cu-Al ternary alloys. Furthermore, it was found that martensitic transformation temperatures (Ms, Mf, As and Af) of Zr-Cu-Al alloys can be controlled by the concentration of added Al. In addition, Vickers hardness test results suggest that the hardness of ZrCu (parent phase) is lower than that of ZrCu (martensite phase). © 2021 Society of Materials Science Japan. All rights reserved.