Effect of Heat Treatment on Microstructure and Wear Behavior of Laser Clad FeCoCrMoNi High-Entropy Alloy Coatings

The microstructure and wear behavior of laser cladding FeCoCrMoNi high-entropy alloy (HEA) coating on Q235 steel substrate were studied. The coatings consisted of an FCC matrix, σ precipitates, and μ precipitates. With increasing heat treatment temperature, the μ phase precipitated and grew from the interdendritic σ phase, while the tip σ phase also precipitated from the FCC matrix. The number of dual precipitates reached its peak at 850 °C. Further, an increase in heat treatment temperature led to the replacement of the interdendritic σ phase by μ phase. The wear resistance of the coatings was closely related to the microstructural evolution. That is, the strengthening effect of the precipitated phase improved the wear resistance. The wear resistance of the coatings initially decreased and then, increased with increasing heat treatment temperature. At 850 °C, the coating has the best wear resistance due to its lowest wear rate, surface roughness and friction coefficient. The dominant wear mechanism being abrasive wear.