The effect of α1 plates on the martensitic transformation and shape memory effect in a β Cu–Zn alloy

Abstract

The martensitic transformation and shape memory effect (SME) in a β Cu–Zn alloy containing various amounts of α1 plates have been investigated. The results showed that the characteristic temperature of martensitic transformation decreased as the isothermal aging time increased. The crystal structure, twin relationships between martensite variants, and characteristics of martensitic transformation of the β Cu–Zn alloy were not affected by the existence of α1 plates. However, the α1 plates were distributed homogeneously in the parent phase and functioned as grain boundaries, hindering the progress of martensite variants, and reducing the effective grain size of the parent phase and the size of self-accommodating plate groups formed upon cooling. In addition, the strain recovery due to the SME decreased as the isothermal aging time increased (the quantity of α1 plate increased) and/or imposed prestrain increased. Nevertheless, the SME mechanism in the β Cu–Zn alloy containing α1 plates was not affected by the presence of the α1 plates.