Influence of heat treatment on microstructure, mechanical behavior, and soft magnetic properties in an fcc-based Fe29Co28Ni29Cu7Ti7 high-entropy alloy

The influence of heat treatment (homogenization) on the microstructure, mechanical behavior, and soft magnetic properties of a face-centered cubic (fcc)-based high-entropy alloy (HEA), Fe29Co28Ni29Cu7Ti7, fabricated by casting, was investigated in detail. The as-cast Fe29Co28Ni29Cu7Ti7 HEA was composed of a primary fcc phase containing coherent dispersed L1(2) nanoprecipitates and trace amounts of a needle-like phase. The tensile yield strength (sigma(0.2)), ultimate strength, and total elongation of the as-cast alloy are 917 MPa, 1060 MPa, and 1.8%, respectively. Following homogenization, the alloy having a single fcc phase shows a decrease of similar to 55% in yield strength and a decrease of similar to 36% in ultimate strength; however, the total elongation is increased from 1.8 to 52%. Saturation magnetization (M-sat) is decreased from 111.54 to 110.34 Am-2/kg, by contrast, coercivity (H-c) is increased from 266.65 to 966.89 A/m. The dissolution of precipitates and grain growth are mainly responsible for the changes in magnetic properties and mechanical behavior.