The influence of the pre-placed powder layers on the morphology, microscopic characteristics and microhardness of Ti-6Al-4V/WC MMC coatings during laser cladding

Abstract

Ti-6Al-4V/WC metal matrix composite (MMC) coatings provide an adequate solution for high wear resistance application of Ti-6Al-4V. Laser cladding process, which has been extensively researched as an advanced repairing and strengthening technology, is considered to be an important candidate to combine the ductile metal matrix and high surface properties. In this study, the powder-presetting laser cladding technology was employed to fabricate WC particles reinforced MMC coatings applying pre-placed pure WC powder layers and Ti-6Al-4V/WC powder layers, respectively. These experiments were performed to investigate the influence of the pre-placed powder layers on the Ti-6Al-4V/WC MMC coatings. The morphology, microscopic characteristics and microhardness of the coatings were scrutinized using optical microscopy, X-ray diffractometer, scanning electron microscopy and Vickers hardness tester. The experimental results show that the coatings fabricated from pre-placed Ti-6Al-4V/WC powder are enhanced more obviously in comparison with pure WC powder, which is related to the more uniform distribution of WC, smooth morphology of coatings and homogeneous distribution of microhardness.