Microstructure evolution and properties of laser cladding Nb containing eutectic high entropy alloys

High entropy alloys (HEAs), as new structural alloys, are expected to achieve their breakthrough application in the field of laser additive repair. In this work, Al0.5 CoCrFeNiNbx (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) high-entropy alloy coatings (HEAcs) were prepared on the surface of H13 (4Cr5MoSiV1) steel using laser cladding (LC) technology, and the effects of Nb content on the hardness and wear resistance of Al0.5CoCrFeNi HEAcs were investigated. The phase composition, microstructure, and element distribution of the coatings were characterized, respectively. The results showed that the Al0.5CoCrFeNi HEAcs mainly consisted of the face-centered cubic (FCC) phase, and the addition of Nb promoted the generation of laves phase. The addition of Nb achieved the transformation of the internal microstructure from sub-eutectic to eutectic and then to hyper-eutectic. The coatings containing Nb show significant grain refinement, a gradual increase in hardness, and a significant improvement in wear resistance. The wear mechanism was mainly fatigue wear and abrasive wear.