The refinement treatment of martensite in Cu–11.38 wt.%Al–0.43 wt.%Be shape memory alloys

Abstract

The refinement treatment of martensite in Cu–11.38 wt.%Al–0.43 wt.%Be (Cu–22.71 at.%Al–2.57 at.%Be) shape memory alloy was investigated in this work. The results show that the aging treatment at a temperature near the eutectoid temperature caused numbers of oval-like renucleated parent phase in the matrix. Following the TEM-EDX analysis, a concentration gradient of Al content is caused because the Al-rich renucleated phase formed in the matrix. Therefore, the occurrence immediately provides potential sites for heterogeneous nucleation. When a large number of martensites grow simultaneously, mutual collision and obstruction occur, creating a cluster microstructure of fine martensite and improving the recovery ability of the alloy.