Fabrication and Characterization of AlxCrCuFeNi2 High-Entropy Alloys Coatings by Laser Metal Deposition

High-entropy alloys (HEAs) are becoming new hot spots in the metallic materials community, which are defined to contain equiatomic or close-to-equiatomic compositions. HEAs can possess many interesting mechanical properties, and in particular, they have the great potential to be used as coating materials requiring high hardness and wear resistance. In this study, the feasibility of fabrication AlxCrCuFeNi2 (x=0,0.75) HEAs was investigated via laser metal deposition from elemental powders. The microstructure, phase structure, and hardness were studied by an optical microscope, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), electron backscatter diffraction (EBSD) and Vickers hardness tester. The bonding between the AlxCrCuFeNi2 (x = 0,0.75) HEAs and AISI 304 stainless steel were good combinations. The Al0.75CrCrFeNi2 alloy consisted of columnar dendritic microstructure with Al/Ni enrichment in the dendritic regions. The phase structure of the AlxCrCuFeNi2 (x = 0,0.75) HEAs were face center cubic structure as identified by EBSD. Vickers hardness results indicate that the average hardness of CrCuFeNi2 HEA was 175 HV. With the addition of aluminium, the Vickers hardness of Al0.75CrCuFeNi2 HEA increased to 285 HV.