Mechanical, corrosion and magnetic behavior of a CoFeMn_1.2NiGa_0.8 high entropy alloy

In this study, a magnetic high entropy alloy (HEA) of CoFeMn_1.2NiGa_0.8 was designed and prepared by arc melting in order to investigate its mechanical, corrosion and magnetic behavior. The results show that the alloy mainly possesses body-centered cubic (BCC) phase and face-centered cubic (FCC) phase. A high compressive strength of 1450 MPa, a strain of 18.5 % and a relatively low yield strength of 303 MPa in as-cast condition at room temperature can be achieved in the present alloy. In-situ high-energy X-ray diffraction technique was employed to reveal the deformation mechanism of CoFeMn_1.2NiGa_0.8 under uniaxial compression and the results show that the competition between BCC phase and FCC phase plays a significant role during the compressive process. The corrosion behavior of CoFeMn_1.2NiGa_0.8 was investigated in 3.5 wt% NaCl solution and it turned out that the alloy possessed good corrosion resistance. At last, the magnetic behavior of the CoFeMn_1.2NiGa_0.8 alloy was studied and it can present a high saturation magnetization of 94.5 emu/g and a coercivity of 26.4 Oe at 4 K. This work indicates that the present CoFeMn_1.2NiGa_0.8 HEA has promising applications as future magnetic functional materials.