激光熔覆Fe0.5NiCoCrCuTi高熵合金涂层的微观结构及性能

采用激光熔覆工艺在40Cr钢表面制备了Fe0.5NiCoCrCuTi高熵合金涂层，利用带有能谱的扫描电子显微镜（SEM/EDS）、显微/维氏硬度计、摩擦磨损试验机、电化学工作站等对Fe0.5NiCoCrCuTi高熵合金微观结构进行分析并测试其硬度、耐磨性能、耐蚀性能。结果表明:Fe0.5NiCoCrCuTi高熵合金试样主要由涂层、热影响区及基体组成，涂层无气孔、裂纹等缺陷，与基体呈冶金结合；涂层主要由两种形貌的片状组织组成，晶粒排列紧密，晶粒表面分布着细小的粒子；涂层出现元素偏析，但程度较小；细晶强化、固溶强化、析出强化的共同作用使得Fe0.5NiCoCrCuTi涂层具有高硬度，表面最高硬度为857 HV，约为基体40Cr钢的3.3倍，高硬度及细小尺度析出物为涂层的耐磨性提供了保证；Fe0.5NiCoCrCuTi高熵合金涂层在3.5% NaCl和0.5 mol/L H2SO4溶液中的耐蚀性能优异，与304不锈钢相比，自腐蚀电流密度降低两三个数量级，自腐蚀电位分别正移0.230、0.161 V。

Microstructure and properties of Fe0.5NiCoCrCuTi high entropy alloy coating prepared by laser cladding

The Fe0.5NiCoCrCuTi high entropy alloy coating was prepared by laser cladding on 40Cr steel surface. The microstructure, hardness, wear resistance and corrosion resistance of Fe0.5NiCoCrCuTi high entropy alloy were investigated by means of scanning electron microscopy and energy dispersive spectroscopy(SEM/EDS), micro/Vickers hardness tester, friction and wear tester and electrochemical workstation. Experimental results show that Fe0.5NiCoCrCuTi high entropy alloy is mainly composed of coating, heat affected zone and the substrate. The coating has no pores, cracks and other defects, metallurgical bonding with substrate; the coating is mainly composed of two kinds of lamellar microstructure morphology, the grains closely arranged, fine particles are distributed on the grain surface. There is element segregation in the coating, but to a relatively small extent. Under the combined action of fine-grained strengthening, solid solution strengthening and precipitation strengthening, the Fe0.5NiCoCrCuTi coating has high hardness, the maximum surface hardness is 857 HV, about 3.3 times as much as the 40Cr steel. High hardness and fine scale precipitates provided a guarantee for the wear resistance of the coating. The corrosion resistance of Fe0.5NiCoCrCuTi high entropy alloy coating in 3.5% NaCl and 0.5 mol/L in H2SO4 solutions are excellent, compared with 304 stainless steel, the corrosion current density were decreased by 2 and 3 orders of magnitude respectively, the corrosion potential were shift toward positive direction for 0.230 V and 0.161 V respectively.