Preparation process and experimental study of laser cladding WC-12Co gradient coating on M2 high-speed steel surface

Using COMSOL numerical simulation software, numerical simulation and analysis were conducted on the surface cladding of WC-12Co coating and the WC-12Co gradient coating with added Ni60 transition layer on M2 high-speed steel. Investigate the changing rules of temperature gradient over time, and summarize the methods of heat coupling control in gradient cladding based on gradient experiments and analysis of the macroscopic morphology and microscopic structure of the coating. The simulation and experimental results show that the temperature gradient of the WC-12Co gradient coating prepared by adding the Ni60 transition layer is much smaller than that of the WC-12Co coating prepared by direct fusion deposition. Adding the Ni60 transition layer to prepare the WC-12Co coating can utilize the laser power of the direct fusion deposition process, as well as expand the power range of the fusion deposition process, which is beneficial for improving the efficiency of the fusion deposition process. Adding the Ni60 transition layer enhances the coating’s internal structure by reducing defects and refining the grain size. Although the diffusion of Ni elements within the Ni60 layer may slightly reduce the hardness of the WC-12Co coating, its hardness still exceeds that of the substrate.