Martensitic transformation of (Ni55.3Fe17.6Ga27.1)100-xCox magnetic shape memory alloys

The effects of Co on the martensitic transformation and magnetic properties of Ni-Fe-Ga magnetic shape memory alloys were investigated. An unusual phenomenon of one martensitic transformation and two intermartensitic transformations in the differential scanning calorimetry curve for Ni55.3Fe17.6Ga27.1 alloy was observed. With 3 at.% Co addition in Ni55.3Fe17.6Ga27.1 alloy, the Ms temperature increased from 313.44 to 405.07 K, the saturation magnetization was improved from 21.64 to 97.67 emu/g and the magnetocrystalline anisotropy constant was enhanced from 1.253 × 106 to 4.035 × 106 erg/cm3. In addition, the magnetic susceptibility also increased obviously in the low magnetic field. It is suggested that alloying with Co is an effective way to develop low-field, high-temperature and high-performance Ni-Fe-Ga magnetic shape memory alloys