Phase selection, microstructure and properties of laser rapidly solidified FeCoNiCrAl2Si coating

A high-entropy alloy (HEA) coating with the composition of FeCoNiCrAl2Si was prepared under laser-induced rapid solidification condition. The difference of atomic radius between Si (1.11 Å) and Al (1.43 Å) elements increases the atomic packing density. The coating has high microhardness (900 HV0.5) and electrical resisitivity (265 μΩ mm) with simple supersaturated ordered and disordered body-centered cubic (BCC) structure. Besides the thermodynamic reason of high-entropy effect on the phase selection in the coating, the calculated incubation times of the nucleation for various competing phases during solidification indicate that the high cooling rate also plays a key role on preventing precipitation of intermetallic compounds.