Effect of laser cladding process on the microstructure and properties of high entropy alloys

In order to investigate the effect of laser cladding process on the microstructure and properties of high entropy alloys, laser cladding technology is used to prepare high entropy alloy coatings on the surface of Q235 substrates under different cladding processes. The microstructure of the high-entropy alloy coating is observed and analyzed by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometer, etc. The hardness and wear resistance of the coating are studied by micro hardness tester and friction wear tester. The results show that the coating width increases and the coating surface becomes flatter when the laser power increases for a certain scanning speed in macroscopic morphology. The width of the coating decreases when the scanning speed increases with a certain laser power. The phase structure is mainly composed of body-centered cubic (BCC) and face-centered cubic (FCC) structures. In microstructure, as the scanning speed increases or the laser power decreases, the grains in the coating become smaller and there is a tendency for the cellular crystals to grow into dendrite crystals in some areas. The hardness of the coating is significantly higher than that of the substrate, up to 553 HV; the wear resistance is better than that of the substrate.