Laser surface engineering of Ti–6Al–4V with TiO2/Al2O3 composite powder for improved wear resistance

Abstract

Titanium (Ti) alloys are often the materials of choice used in light-weighting strategies in manufacturing. However, their tribological performance needs to be improved. In this work, a laser surface engineering process using titania/alumina (TiO₂/Al₂O₃) composite powders was developed for Ti–6Al–4V alloy to enhance its wear resistance. This process resulted in the formation of a novel Al_xO_y/TiO_xN_y/α-Ti composite coating. The Al_xO_y particles were firmly embedded in the matrix, forming a semi-coherent interface with TiO_xN_y dendrites, which could strengthen the composite coating. The incorporation of fine Al₂O₃ particles also improved the laser absorptivity of the starting powders and decreased melt viscosities, leading to the considerable reduction in the porosity and crack density in the coatings. The wear resistance of the coatings made with the composite powders was superior to that made with the pure TiO₂ powder.