激光熔覆FeCo0.5CrNi1.5B0.5Nb0.1高熵合金涂层组织调控及耐磨耐蚀性能研究

    Microstructure Control and Wear, Corrosion Resistance of Laser Cladding FeCo0.5CrNi1.5B0.5Nb0.1High Entropy Alloy Coating

    • 摘要: 针对真空泵转子轴在实际工况中的表面磨损、腐蚀问题,采用激光熔覆技术在球墨铸铁(QT500-7)表面制备了FeCo0.5Cr Ni1.5B0.5Nb0.1高熵合金涂层,并研究不同激光扫描速度(300、400、500、600 mm/min)对该涂层物相组成、显微组织、显微硬度、耐磨及耐蚀性能的影响。结果表明,随着激光扫描速度的增加,涂层发生了局部相变,晶粒细化,晶间逐渐出现硼化物、碳化物沉淀,起到了析出强化作用。涂层显微硬度及耐磨耐蚀性能随扫描速度的增加先增加后降低。当扫描速度为500 mm/min时,涂层物相由FCC、Laves相和少量硼化物、碳化物组成,强韧兼具,涂层显微硬度最高,为632.3 HV0.2,大约为基体的2.75倍,且其具有最优的耐磨性和耐蚀性。

       

      Abstract: In view of the surface wear and corrosion problems of the vacuum pump rotor shaft in the actual working conditions, FeCo0.5Cr Ni1.5B0.5Nb0.1high entropy alloy coating was prepared on the surface of nodular cast iron(QT500-7) by laser cladding technology. The effects of different laser scanning speeds(300 mm/mi n, 400 mm/min, 500 mm/min, 600mm/min) on the phase composition, microstructure, microhardness, wear resistance and corrosion resistance of the coating were studied. The results show that with the increase of laser scanning speed, the coating undergoes local phase transformation, the grains are refined, and boride and carbide precipitate gradually between grains, which plays a role in precipitation strengthening. The microhardness, wear resistance and corrosion resistance of the coating first increase and then decrease with the increase of scanning speed. When the scanning speed is 500 mm/min, the coating phase is composed of FCC, Laves phase and a small amount of borides and carbides, with both strength and toughness. The microhardness of the coating is highest, which is 632.3 HV0.2, about 2.75 times than that of the substrate, and it has the best wear resistance and corrosion resistance.

       

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