Influence of Al addition on martensitic transformation and magnetic properties of Ni-Fe-Ga ferromagnetic shape memory alloys

The effect of the fourth element Al on the martensitic transformation and magnetic properties of polycrystalline Ni-Fe-Ga alloys is investigated. A complete thermoelastic martensitic transformation in Ni-Fe-Ga-Al alloys was observed in a range of 309-394 K. Martensitic transformation temperatures of Ni-Fe-Ga alloys are obviously decreased by the substitution of Al for Ga element: the addition of 1% Al can decrease the martensitic transformation temperature by about 68 K. On the other hand, the substitution of Al for Ga increases the saturation magnetization and decreases the saturation magnetic field.