Effect of Nb Addition on Microstructure and Magnetic Properties of Ni_(55)Fe_(17.5)Ga_(27.5) Ferromagnetic Shape Memory Alloy
The effects of Nb addition on the microstructure and magnetic properties of Ni55Fe17.5Ga27.5ferromagnetic shape memory alloy were investigated by metallurgical microscope, X ray diffraction and vibrating sample magnetometer. The results show that Ni55Fe17.5Ga27.5alloy has two phase coexistence, such as 14 M monoclinic martensitic structure and face-centered cubic structure of γ phase at room temperature,little effect on morphology and crystal structure of the alloy with adding 1at% of Nb, when 2at% of Nb is added into the alloy. The width of martensite variant in alloy is significantly smaller.When adding 3at% of Nb, the alloy has three phase coexistence, and the martensite variant width decreases furtherly. When adding 1at% of Nb, the saturation magnetization and curie temperature of the alloy increase. When further adding Nb into the alloy, the saturation magnetization and curie temperature of the alloy decrease.