Gang Li

This study examines the influence of different WC–TiC contents on the microstructure and high-load wear resistance of Ti-based coatings prepared on Ti–6Al–4V by plasma transferred arc welding, as well as on the tensile response of the corresponding coating/substrate composite structures. The amount of retained hard constituents rose accordingly with increasing WC–TiC addition. WC-associated constituents were located mainly in the central and lower portions of the deposited layer, whereas TiC-related constituents were distributed more evenly within the titanium-based matrix. XRD analysis revealed the existence of α-Ti together with WC and TiC and also showed that the principal diffraction peak of the Ti matrix shifted slightly toward a lower angle. The average surface microhardness increased from about 335 HV for the substrate to about 707, 757, and 793 HV for the 10, 15, and 20 wt. % coatings, respectively. Although the coating/substrate composite specimens exhibited lower tensile properties than the uncoated substrate, the 20 wt. % composite specimen showed the most favorable tensile response among the three composite specimens, with a mean ultimate tensile strength of 552.9 MPa and a mean total elongation of 10.60%. The 15 wt. % coating exhibited the lowest average friction coefficient of 0.133 under reciprocating dry sliding at a load of 20 N, whereas the 20 wt. % coating presented the lowest mean wear rate of 2.6 × 10−7 mm3/(N m), representing a 39.5% reduction compared with the substrate. In general, the 15 wt. % WC–TiC coating was more effective in reducing friction, while the 20 wt. % WC–TiC coating offered the best wear resistance.