Evaluation on Tribological Performance of Ti-6Al-4V Alloy Modified Using Powder Composite Electrode-Assisted Electrical Discharge Coating

Abstract

The wear behavior of the WC-Cu-coated Ti-6Al-4V alloy with composite electrode-assisted electrical discharge coating (EDC) has been studied using the pin-on-disc method. The effect of normal force (10–30 N), sliding speed (16–36 m/s) and sliding time (240–720 s) on the wear rate (WR) and friction coefficient (FC) has been examined. The WR ranged from 0.0002821 to 0.0003880 mm³/N m with a standard deviation of ± 0.00003 mm³/N m, while the friction coefficient ranged from 0.0230 to 0.0454 with a standard deviation of ± 0.003. The results were compared with the uncoated Ti-6Al-4V alloy, showing a significantly higher wear rate of 0.0004500 mm³/N m and friction coefficient of 0.048. The WR and FC both increased with the increasing of normal force and sliding speed, but WR decreased at higher sliding time. In the mild wear region (10 N, 16 m/s, 240 s), grooves and micro-cutting were noticed, while plastic deformation and oxidative wear were identified in the severe wear region (20 N, 26 m/s, 480 s). In the ultra-severe wear region (30 N, 36 m/s, 720 s), the melting of the coating materials caused microcracks and fatigue wear, resulting in increased WR and FC. Compared to conventional coatings, the WC-Cu coating demonstrated improved wear resistance, highlighting its potential for applications in automotive and aerospace industries.