In-situ synthesis of NiCoCrMnFe high entropy alloy coating by laser cladding

Abstract

Improving the service life of the casting die is an important research topic. Due to the excellent wear resistance of the high entropy alloy, in-situ synthesis of a NiCoCrMnFe high entropy alloy coating on the H13 die steel through multilayer laser cladding was carried out in this study, and the microstructure, composition, phase, microhardness and wear resistance of the coating were investigated and compared with that of the untreated steel substrate. The results show that a high entropy alloy coating with a thickness of about 0.6 mm was formed, with its composition close to the design composition, and the phase is basically a single-phase FCC solid solution. Microhardness of the cladding layer is higher than 500 HV, over 2.5 times as that of the untreated substrate, and there are no microcracks around the indentations. Under the same friction conditions, the average width of the wear mark decreases from 0.71 mm of the substrate to 0.48 mm of the high entropy alloy layer, and the wear rate of the cladding layer decreases by 63.2% compared with the substrate. Meanwhile, hot erosion of the high entropy alloy coating by liquid Al alloy is far less serious than that of the substrate under the same condition. The in-situ synthesized NiCoCrMnFe high entropy alloy coating by laser cladding can significantly improves the surface microhardness, wear resistance and especially hot erosion resistance of the H13 die steel, which can be used to optimize the surface properties of the die.