Study on the dilution mechanism of laser-cladding AlCoCrFeNi high-entropy alloy coatings

Abstract High-performance AlCoCrFeNi high-entropy alloy (HEA) coating is manufactured by employing laser cladding to enhance the wear-resistant properties of 45# steel. Finite element simulations and experiments are combined to examine the effects of dilution rate on coating properties. The findings demonstrate that the rate of dilution increases as the speed of the laser scan increases, leading to a noticeably greater Fe concentration in the coating. Due to the low solidification rate at 4 mm/s, a moderate convection can be formed, which leaves the Fe content comparable to that of the other elements. Convection of the melt pool is exacerbated by the faster scanning speed, which allows more Fe to flow from the substrate into the coating and raises Fe concentration. The average values of microhardness are 581.54 HV, 601.86 HV, and 276.75 HV at scanning speeds of 4, 6, and 8 mm/s, respectively. Moderate dilution of the substrate can increase the microhardness, while excessive dilution can lead to a higher Fe concentration in the coating, which seriously deteriorates the properties. This study provides a guide to fabricating high-performance AlCoCrFeNi HEA coatings for 45# steel.