Effects of Gd addition on microstructure and shape memory effect of Cu–Zn–Al alloy

As modification of Cu–Zn–Al shape memory alloys (SMAs), the characteristics of Cu–Zn–Al alloys containing different amount of rare earth Gd addition are investigated by optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and the bending method. The results show that Gd addition refines the grains of Cu–Zn–Al alloys obviously, and there are small spherical Gd-rich phases precipitated in the matrix of the alloys. There is no effect of Gd addition on the martensitic transformation type martensitic transformation temperatures of Cu–Zn–Al alloys. The shape recovery ratio is evidently improved with Gd addition, and the shape memory effect of Cu–Zn–Al alloy is the best when the content of Gd is between 0.08 and 0.12 wt.%.