(1. 常州大学 机械工程学院，常州 213164；
2. 常州大学 江苏省绿色过程装备重点实验室，常州 213164)
摘 要: 以Cr12MoV冷模具钢为研究对象，采用不同的激光功率密度在Cr12MoV表面熔覆WC质量分数为40%的Ni60WC40复合涂层。随后对熔覆后试样的涂层熔覆界面、熔覆表面微观组织和成分的形成进行探讨，并通过摩擦磨损实验研究各熔覆层的耐磨损性能。结果表明：随着激光熔覆功率密度的提高，熔覆层厚度逐渐增大，熔覆区纵向组织从尚未完全熔化的团絮状及棒状晶逐渐向晶粒更为细小的花瓣晶转变；熔覆区横向组织从长短不一的花瓣晶及鱼骨状树枝晶逐渐向晶粒尺寸更为细小的长条形枝晶转变；CrNiC、CrFeNi等铬碳化合物和WN、CoN等金属固溶体的产生增强涂层的细晶强化作用。在激光功率密度为111.30 W/mm2时，试样表现出相对最优的耐磨性能。
关键字: 激光熔覆；熔覆区；摩擦；磨损；Ni60WC40
（1. School of Mechanical Engineering, Changzhou University, Changzhou 213164, China;
2. Jiangsu Key Laboratory of Green Process Equipment, Changzhou University, Changzhou 213164, China）
Abstract:The composite coatings of Ni60WC40 (mass fraction, %) were cladded on Cr12MoV mold steel by laser cladding with different power density. The interface and surface microstructure of cladded coatings and the surface composition were investigated, and moreover, the wear resistance of cladded coatings was tested. The results indicate that the thickness of cladded coating increases with the raising of laser cladding power density. In addition, the unmelted flocculent and rod-shaped crystals, which are in the longitudinal microstructure of the cladded zone, gradually transforms to the finer petal crystals. The lateral microstructure of cladded coating is transferred from petal crystals with various sizes and fishbone dendrites to long strip dendrites with finer grain size. The generation of chromium carbons (CrNiC, CrFeNi, etc.) and metal solid solution (WN, CoN, etc.) improves the coatings strengthened subjected to the fine grain. With 111.30 W/mm2 of laser power density, the coating performs the best running-in tribological behaviors.
Key words: laser cladding; cladded zone; friction; wear; Ni60WC40
