Effect of Fe content on the microstructure and wear resistance of AlCoCrFeNi high-entropy alloy coating prepared by laser cladding

The Fe is considered to be an important element for promoting the industrial application of high entropy alloys due to its great economic benefits. In this study, the AlCoCrFexNi (x = 0, 0.5, 1 and 1.5, molar ratio) HEAs coatings are prepared by means of laser cladding to investigate systematically the influence of Fe content on the phase structure, microstructure and wear resistance. The results show that all coatings consist of the BCC and B2 phases. For AlCoCrNi and AlCoCrFe0.5Ni coatings, the spherical/ellipsoidal BCC phases are precipitated on the B2 primary phase within the grain. The shape of BCC and B2 coherent precipitation phases for AlCoCrFeNi and AlCoCrFe1.5Ni coatings evolves to a weave-like BCC + B2 spinodal decomposition structure. AlCoCrFe0.5Ni coating has the highest microhardness and lowest wear rate due to the fine grain strengthening, dislocation strengthening and the formation of a special microstructure by precipitation of the spherical/ellipsoidal BCC phases on the B2 primary phase, which resists the friction ball indentation, preventing the plowing of large-sized wear debris from the sample surface. This research contributes to advancing the industrial application of economical and wear-resistant HEAs coatings.