Tribological Behaviors of Ti6Al4V with Surface Plasma Molybdenized

This paper was directed at improving the wear resistance of titanium alloy Ti6Al4V by double-glow plasma surface alloying (DPSA) technology. A molybdenized layer was successfully formed on Ti6Al4V by the DPSA treatments. The microstructure, composition distribution, phase structure and hardness were analyzed by SEM/EDS, XRD and vickers micro-hardness tester. The molybdenized layer was composed of Mo-deposited layer and Mo-diffusing layer. The average surface micro-hardness of the surface modified layer was 1170.8 HV0.1, which was much higher than that of the Ti6Al4V substrate. Tribological characterization was carried out by the ball-on-disc tribometer at room temperature and 500 degrees C. The molybdenized layer significantly reduced the wear rate of the Ti6Al4V alloy, which is only about 6.6% and 4.9% of those of the untreated specimens at room temperature and 500 degrees C, respectively. Due to the good self-lubricating effect of Mo elements at high temperature conditions, the friction coefficient and wear rate of the molybdenized layer were both reduced at 500 degrees C, compared to at room temperature.