Microstructure, mechanical properties and corrosion resistance of an as-cast fine-structured Cr-Fe-Ni-Al-Si high entropy alloy

In this paper, a CrFeNiAl0.28Si0.12 high entropy alloy (HEA) was designed and fabricated by arc-melting. It is found that, this Co-free as-cast HEA is mainly composed of fine FCC and BCC phases that have close correlation with solid-state phase transformation during cooling after solidification. It shows high mechanical properties combining ultimate tensile strength of ∼1130 MPa and plasticity of ∼8%. Moreover, it also has good corrosion resistance comparable to stainless steels. This work provides a novel route for designing high-performance low-cost HEAs with outstanding mechanical properties and corrosion resistance produced simply via casting under relatively low cooling rates, which is beneficial for wide applications of this series of materials under harsh environment.