Microstructure and Wear Properties of Laser Cladding WC/Ni-Based Composite Layer on Al-Si Alloy.

The microstructural and wear properties of laser-cladding WC/Ni-based layer on Al-Si alloy were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and wear-testing. The results show that, compared with the original specimen, the microhardness and wear resistance of the cladding layer on an Al-Si alloy were remarkably improved, wherein the microhardness of the layer achieved 1100 HV and the average friction coefficient of the layer was barely 0.14. The mainly contributor to such significant improvement was the generation of a WC/Ni-composite layer of Al-Si alloy during laser cladding. Two types of carbides, identified as MC and MC, were found in the layer. The wear rate of the layer first increased and then decreased with the increase in load; when the load was 20 N, 60 N and 80 N, the wear rate of layer was1.89 × 10 mm·m, 3.73 × 10 mm·m and 2.63 × 10 mm·m, respectively, and the average friction coefficient (0.14) was the smallest when the load was 60 N.