Laser Power‐Dependent Microstructure Evolution and Wear Behavior of Laser‐Cladded CoCrFeNiAl _0.7 High‐Entropy Alloy Coatings

The CoCrFeNiAl x high‐entropy alloy (HEA) system offers high strength, high hardness, and well wear resistance owing to its multiprincipal element composition and special structure. However, the high cost and poor castability of bulk HEAs restrict their structural use, making HEA coatings a practical and high‐performance alternative. The CoCrFeNiAl 0 . 7 dual‐phase high‐entropy alloy (DP‐HEA) coatings were prepared on compacted graphite iron (CGI) substrates via laser cladding at the laser powers of 2500, 3000, 3500, and 4000 W. The effects of laser power and on the wear resistance of CoCrFeNiAl 0 . 7 DP‐HEA coatings were investigated. The microstructure, phase composition, and wear behavior were characterized using scanning electron microscopy, X‐ray diffraction, and pin‐on‐disk wear tests. High‐temperature wear tests were conducted at 50°C, 300°C, and 500°C to analyze the evolution of wear mechanisms. The coating prepared at 3000 W exhibited the lowest friction coefficient and least wear mass loss, attributed to the formation of a uniform oxide layer and a well‐balanced face‐centered cubic/body‐centered cubic dual‐phase structure. At elevated temperatures, the wear mechanism transited from abrasive wear to oxidative wear, with oxide layers playing a critical role in reducing wear rate despite material softening.