Effects of Mo on microstructure and mechanical properties of Fe2Ni2CrMox eutectic high entropy alloys

Eutectic high-entropy alloys (EHEAs) have drawn extensive attention due to their excellent castability and remarkable combination of strength and plasticity. In this study, a new Fe2Ni2CrMox (x = 0.25, 0.50, 0.75, 1.0, 1.25, 1.50) EHEA family was designed and prepared, with the dependence of microstructural and mechanical evolution on the Mo addition investigated. As the increase of Mo addition in the Fe2Ni2CrMox EHEA, the microstructure evolves from hypoeutectic (x = 0.25) to near-eutectic (x = 1.25) and then to hypereutectic (x = 1.50), where the stacked lamellae consist of a face-centered cubic (FCC) phase and a topological close-packed (TCP) sigma phase. Among all the compositions, the Fe2Ni2CrMo1.5 EHEA exhibits the most excellent comprehensive mechanical properties, with the yield strength, fracture strength and compressive plasticity being 1503 MPa, 2199 MPa and 17.6%, respectively.