No abstract

Ni-WC composite coatings on 35CrMoV alloy surface were successfully prepared by mechanical vibration field-assisted laser cladding technology. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to study the microstructure of the composite coatings without vibration and at different vibration frequencies; the phase composition of the cladding layer was studied by X-ray diffraction (XRD); and an energy dispersive spectrometer (EDS) was used for elemental plane scanning analysis. The grain growth trend under different convection directions was simulated. The wear resistance and mechanical properties of the composite coating were analyzed by friction and wear testing machine, three-dimensional surface profiler, and microhardness tester. The vibration field generated by the self-improved shaking table device is used to assist laser cladding. The effect of mechanical vibration on the quality of the cladding layer was studied. The results show that compared with the coating without mechanical vibration, an appropriate increase in vibration frequency contributes to the refinement of the grains. The original coarse dendrite structure becomes a fine needle-like structure, and the fine grain size gradually decreases. The application of vibration can improve the effect of grain refinement. The vibration makes the grain size distribution more uniform and the microhardness fluctuation of the cladding layer decreases. The experimental results show that mechanical vibration can improve the microstructure uniformity of the coating by selecting suitable vibration parameters. The average friction coefficient and wear width are reduced, and the microhardness is also increased.