Ni-Co-Mn-Sn quaternary alloys: magnetic hysteresis loss reduction and ductility enhancement by iron alloying

Abstract

The influence of Fe-alloying on the structural transition temperatures, microstructure, and mechanical and magnetocaloric properties of polycrystalline Ni41Co9−xFexMn40Sn10 (at. %) (x = 0–3) alloys has been studied. The substitution of Fe for Co introduced the so-called γ phase when the Fe content exceeds 1 at. %. The transformation temperatures decreased almost linearly with increasing Fe content without alteration of the transformation sequence. The compressive strength and maximum compressive strain increased to 1270 MPa and 21.3 % for Fe content of 3 at. %. In addition, the fracture type changed gradually from typical intergranular cracking to transgranular cracking with increasing Fe content. Magnetic field-induced reverse martensitic transformation was modified by increasing the Fe alloying, leading to the reduction of magnetic hysteresis loss (∼ 82.5 % drop after addition of 3 at. % Fe) but at the expense of a significant reduction in the maximum magnetic entropy change value.