Study on tribological properties of high entropy alloy composite coatings with different tungsten carbide contents in laser cladding

Abstract

The severe working conditions of mining machinery make the wear of its parts extremely serious, thus reducing its service life, increasing the probability of accidents, and may cause huge economic wastage. So promoting the improvement of mining machinery is imperative, and the melting of wear-resistant layer on the surface of wear-prone equipment is a more effective improvement method. The study was performed by laser fusing a composite coating of CoCrFeNiMn high-entropy alloy with different WC contents, and a second phase was generated in the coating by an additive method to achieve the strengthening of the coating. The experiments revealed that all the coatings had FCC phase as the main phase by analyzing the phase conformation, structure, stiffness, and abrasiveness. When the WC dosage exceeded 20 wt.%, Fe₃W₃ (M₆C) carbide reinforced phases with different morphologies were produced in the coatings. Forty wt.% of the coatings showed the highest hardness, which was 3.1 times better than that of the coatings without WC particles, and 30 wt.% of the coatings showed the best abrasiveness. HT0 coatings showed the least friction factor of 0.27. HT600 and HT800 corresponded to friction factors of 0.37 and 0.35, respectively. The coefficient of friction of the coating was most stable after about 3 min at room temperature, and the wear phase took longer after annealing. During the break-in phase, the precipitated phase has a supportive effect and prolongs the break-in period. The coating using the studied method improves the wear resistance of mechanical parts and extends their service life, which has some economic and practical value.