Effect of the Addition of Gd on Ni53Mn22Co6Ga19 High-Temperature Shape Memory Alloy

The rare earth element Gd is added to Ni53Mn22Co6Ga19 high-temperature shape memory alloy to refine the grain size and adjust the distribution of γ phase, and their microstructure, martensitic transformation behaviors, mechanical and shape memory properties were investigated. The results show that the grain size is obviously decreased and the γ phase tends to segregate at grain boundaries with increasing Gd content. Small amounts of Gd-rich phase were formed with 0.1 at.% Gd addition. The martensitic transformation temperature abruptly increases with 0.1 at.% Gd addition, then almost keeps constant with further increasing Gd content. The addition of 0.1 at.% Gd is proved to be beneficial to both tensile stress and strain before fracture, but negative to the shape-memory effect.