Processing effects on the magnetic and mechanical properties of FeCoNiAl_0.2Si_0.2 high entropy alloy

High entropy alloys with the composition of FeCoNiAl_0.2Si_0.2 were prepared by arc melting and induction melting, denoted by A1 and A2, respectively. The samples prepared by these two techniques have a face-centered cubic (FCC) phase structure and a typical dendrite morphology. The tensile yield strength and maximum strength of A2 samples are about 280 and 632 MPa, respectively. Moreover, the elongation can reach 41.7%. These two alloys prepared by the different methods possess the similar magnetic properties. The saturation magnetization and coercivity can reach 1.151 T and 1400 A/m for Al samples and 1.015 T and 1431 A/m for A2 samples, respectively. Phases in A2 samples do not change, which are heat treated at different temperatures, then quenched in water. Only the sample, which is heat treated at 600℃ for 3 h and then furnace cooled, has a new phase precipitated. Besides, the coercivity decreases obviously at this temperature. Cold rolling and the subsequent heat treatment cannot improve the magnetic properties effectively. However, cold rolling plays an important role in improving the strength.