Effect of isothermal ageing on microstructure, martensitic transformation and mechanical properties of Ni53Mn23.5Ga18.5Ti5 ferromagnetic shape memory alloy

The effect of isothermal ageing on the microstructure, martensitic transformation and mechanical properties of Ni53Mn23.5Ga18.5Ti5 alloy has been investigated. The results show that Ni3Ti precipitates are observed in aged samples. The martensitic transformation temperature decreases remarkably with increased ageing time, while the martensitic structure of these alloys is five-layered martensite at room temperature. Additionally, Ti doping can significantly enhance the compressive strength and improve the ductility of Ni–Mn–Ga alloy with the appropriate ageing treatment.