The Influence of Al_2O_3 on the Microstructural Characteristics of a TiB_2/TiC Reinforced Coating Fabricated by Means of Laser Cladding on a Ti-alloy

摘要

A Al_3Ti/Ti_3Al+TiB_2/TiC composite coating was fabricated on the Ti6Al4V alloy by laser cladding with (wt%) Al_3Ti-20TiB_2-20TiC powder blends, which improved the tribology property of the titanium alloys. Nevertheless, when the mass fraction of the TiB_2/TiC pre-placed powders exceeded 40wt.%, the microcrack and pores were present in this composite coating. It was found that Al_2O_3 was able to improve the surface performance of the Al_3Ti/Ti_3Al+TiB_2/TiC composite coating. In this study the Al_3Ti+TiB_2/TiC+Al_2O_3 laser-cladded composite coating on the Ti6Al4V alloy was examined by means of X-ray diffraction (XRD) and a scanning electron microscope (SEM). With the addition of Al_2O_3 this composite coating showed a high and uniform hardness distribution due to the action of the grain refinement strengthening and the hard phases.