Microstructure and mechanical properties in Ni45·4Mn39·5In13·1Gd2alloy with high transformation temperature

A Heusler Ni45·4Mn39·5In13·1Gd2 alloy with high transformation temperature has been obtained by substituting 2 at-%Gd for Mn in a ternary Ni45·4Mn41·5In13·1 ferromagnetic shape memory alloy. It is shown that the microstructure of Ni45·4Mn39·5In13·1Gd2 alloy consists of a matrix and a Gd rich phase. The Ni45·4Mn39·5In13·1Gd2 alloy exhibits a martensitic transformation start temperature of 726 K, and the transformation hysteresis is Af−Ms = 148°C. At room temperature, non-modulated martensite of tetragonal L10 structure is observed in Ni45·4Mn39·5In13·1Gd2 alloy. In addition, it is revealed that the addition of Gd significantly enhances the compressive strength and improves the ductility of Ni45·4Mn39·5In13·1Gd2 alloy.