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在ZG45表面采用真空熔覆技术制备了Ni-Co/WC复合熔覆层,通过SEM、EPMA和XRD观察并分析了熔覆层的显微组织结构和相组成,通过三点弯曲试验研究了熔覆层的弯曲行为,并分析了断口形貌和断裂机理。结果表明,WC颗粒在镍-钴基合金中呈现网状分布,熔覆层的主要组成相有WC、Cr7C3、Cr23C6、Ni3Si、Fe Ni3和镍-钴基固溶体;三点弯曲试验表明,Ni-Co基合金熔覆层与基体结合良好,即使熔覆层朝下承受拉应力时试样自拉应力最大的熔覆层表面开始产生延伸至基体内的纵向裂纹,并无沿结合界面的横向裂纹,而Ni-Co/WC复合熔覆层却在弯曲过程中与基体沿界面发生剥离;断裂试样的基体断口有大量韧窝,基体区域属于韧性断裂,而Ni-Co/WC复合熔覆层的断裂方式包括穿晶断裂和沿晶断裂。
Ni-Co / WC composite cladding layer was prepared on ZG45 by vacuum cladding technique. The microstructure and phase composition of the cladding layer were observed and analyzed by SEM, EPMA and XRD. The three-point bending test The bending behavior of the coating and the fracture morphology and fracture mechanism were analyzed. The results show that the WC particles present a network distribution in the nickel-cobalt based alloy. The main components of the cladding layer are WC, Cr7C3, Cr23C6, Ni3Si, FeNi3 and Ni-Co based solid solution. The Co-base alloy cladding layer is well bonded with the substrate. Even when the cladding layer is under tensile stress downward, the sample begins to have longitudinal cracks extending into the matrix from the surface of the cladding layer with the highest tensile stress and no transverse cracks along the bonding interface , While the Ni-Co / WC composite cladding layer stripped along the interface during the bending process. There were a large number of dimples in the fracture surface of the fracture specimen, and the matrix region was ductile fracture, while the Ni-Co / WC composite cladding layer The fracture modes include transgranular fracture and intergranular fracture.