Effect of annealing temperature on the shape memory properties of cold-rolled dual-phase ni-mn-ga-gd alloy

Abstract

The influence of annealing temperature on the shape memory effect (SME) and recovery ratio of cold-rolled dual-phase Ni58Mn25Ga16.9Gd0.1 high-temperature shape memory alloy were investigated. The results showed that the SME can be improved by appropriate annealing. SME of 6.0% and recovery ratio of 98% were observed in the rolled alloy at 550 -C annealing, which were larger than that of the samples annealed at other temperatures. The annealing temperature was in between the recrystallization temperatures of the martensite and c phase, which leads to the work-hardening state of c phase kept unchanged during annealing process, and therefore, the critical slip stress of c phase increased. Thus, the plastic deformation of c phase reduced during the compression process, and the SME increased.