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The Influence of Al2O3 on the Microstructural Characteristics of a TiB2/TiC Reinforced Coating Fabricated by Means of Laser Cladding on a Ti-alloy
J-N. Li, C-Z. Chen and C-F. Zhang

A Al3Ti/Ti3Al+TiB2/TiC composite coating was fabricated on the Ti6Al4V alloy by laser cladding with (wt%) Al3Ti-20TiB2-20TiC powder blends, which improved the tribology property of the titanium alloys. Nevertheless, when the mass fraction of the TiB2/TiC pre-placed powders exceeded 40wt.%, the microcrack and pores were present in this composite coating. It was found that Al2O3 was able to improve the surface performance of the Al3Ti/Ti3Al+TiB2/TiC composite coating. In this study the Al3Ti+TiB2/TiC+Al2O3 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 Al2O3 this composite coating showed a high and uniform hardness distribution due to the action of the grain refinement strengthening and the hard phases.

Keywords: Titanium alloy (Ti-alloy), Ti6AL4V, laser cladding, CO2 laser, microstructure, intermetallics, metal-matrix composites (MMCs), surface modification

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