Phase evolution and properties of AlxCoCrFeNi high-entropy alloys coatings by laser cladding

Abstract

High-entropy alloys are class of structural materials that have excellent properties and are commonly used in laser additive manufacturing. In this paper, AlxCoCrFeNi (x = 0.5, 1.0, x is the molar ratio) high-entropy alloy coatings were prepared on the surface of H13 steel by using laser cladding technology. The effects of coatings on the phase composition, microstructure, element distribution, grain orientation, wear, and corrosion resistance of AlxCoCrFeNi ((x = 0.5, 1.0) coatings were analyzed. The results show that the Al0.5CoCrFeNi HEAc consists of FCC solid solution phase only, and the Al1.0CoCrFeNi coating consists of BCC/B2 solid solution phase. The microstructure changes from blocky crystals to equiaxial crystals. The average grain size decreased from 65.864 µm to 8.155 µm with the increase of Al content, and the high angle grain boundaries increased gradually with more uniform grain distribution. The average hardness values of AlxCoCrFeNi (x = 0.5, 1.0) coatings are 513.06 HV0.5 and 652.38 HV0.5, respectively. The friction coefficient and mass loss gradually decrease, and the wear form changes from abrasive wear to adhesive wear. AlxCoCrFeNi (x = 0.5, 1.0) HEAcs self-corrosion current density (Icorr) increases from 2.964 × 10−6 Acm−2 to 1.060 × 10−5 Acm−2, and the corrosion resistance gradually decreases.