The effect of alpha(1) plates on the martensitic transformation and shape memory effect in a beta Cu-Zn alloy

The martensitic transformation and shape memory effect (SME) in a beta Cu-Z n alloy containing various amounts of a, plates have been investigated. The results showed that the characteristic temperature of martensitic transfor mation decreased as the isothermal aging time increased. The crystal struct ure, twin relationships between martensite variants, and characteristics of martensitic transformation of the beta Cu-Zn alloy were not affected by th e existence of alpha (1) plates. However, the alpha (1) plates were distrib uted homogeneously in the parent phase and functioned as grain boundaries, hindering the progress of martensite variants, and reducing the effective g rain size of the parent phase and the size of self-accommodating plate grou ps formed upon cooling. In addition, the strain recovery due to the SME dec reased as the isothermal aging time increased (the quantity of alpha (1) pl ate increased) and/or imposed prestrain increased. Nevertheless, the SME me chanism in the beta Cu-Zn alloy containing a, plates was not affected by th e presence of the alpha (1) plates. (C) 2001 Elsevier Science Inc. All righ ts reserved.