【摘要】 采用超高速激光熔覆技术制备了镍基WC涂层,通过SEM、EDS和XRD等对比研究了超高速与低速激光熔覆镍基WC涂层的表面形貌、组织结构与耐磨性能。结果表明,相较于低速激光熔覆,超高速激光熔覆热输入更小、冷却速率更高,制备的镍基WC涂层拥有更好的表面质量;同时,有效减小了基体元素对涂层的稀释,显著降低了WC颗粒的热损伤,使得涂层中碳化物的析出与孔隙生成得到抑制,WC陶瓷颗粒均匀分布,进而显著降低涂层残余应力,避免涂层中裂纹的产生;超高速激光熔覆镍基WC涂层耐磨性能更为优良,磨损机制为磨粒磨损。更多还原

【Abstract】 Steel materials are highly sourced construction materials owing to their robust mechanical properties, and they are widely used in the construction industry for building bridges, tunnels, skyscrapers, towers, ship-metal parts, and other industrial metal applications. However, as steel has poor surface wear resistance, parts are susceptible to failure due to friction damage. To improve the surface wear resistance of steel materials, Ni-based WC coating was prepared by ultra-high-speed laser cladding. Using low-speed laser cladding as a reference, the surface morphology, microstructure, and wear resistance of ultra-high-speed laser cladding of Ni-based WC coatings were studied using SEM, EDS, and XRD,respectively. Experimental results revealed that the Ni-based WC coating prepared by ultra-high-speed laser cladding exhibited better surface quality compared with that prepared by low-speed laser cladding.Comparatively, ultra-high-speed laser cladding requires a smaller heat input and a faster cooling rate.However, the dilution rate of the coating is significantly reduced. In addition, ultra-high-speed laser cladding significantly reduces thermal damage in the WC coating; it inhibits the precipitation of carbides and formation of porosities and promotes the uniform distribution of the WC in the coating, thereby significantly reducing stress localization in the coating and also inhibits crack nucleation in the coating. Because of the reduction of porosities, cracks, and other surface defects in the coating and uniform distribution of WC particles, the Ni-based WC coating prepared by ultra-high-speed laser cladding possesses better wear resistance than that prepared by low-speed laser cladding, and the wear mechanism is abrasion.更多还原