Wear studies of spark plasma sintered ZrO₂ reinforced Ti-6Al-4V alloy

The aim of this paper is to investigate wear and tribological properties of powder metallurgy processed Ti-6Al-4V with additions of ZrO₂ to produce Ti-6Al-4V/ZrO₂ composites consolidated via spark plasma sintering. The spark plasma sintered compacts were examined using optical microscopy (OM) and scanning electron microscopy (SEM) techniques. Dry sliding wear tests were carried out at 5 N and 10 N using a pin-on-disk tribometer. Optical micrographs showed that additions of ZrO₂ to Ti-6Al-4V promoted the formation of agglomerated ZrO₂-rich particles in the matrix of Ti-6Al-4V. The friction coefficient values were very similar for all compositions, with values ranging between 0.35 and 0.55, with the lowest COF value recorded for Ti6Al4V/5ZrO₂ composite at 10 N applied load. Wear and microhardness results indicate that the hardness and the wear resistance improved with increasing content of ZrO₂. The lowest surface degradation was observed for Ti-6Al-4V with 10% ZrO₂. The low wear resistance of Ti-6Al-4V in comparison to Ti-6Al-4V/ZrO₂ composites can be attributed to the low hardness of this alloy. Adding ZrO₂ to Ti-6Al-4V was found to significantly improve the wear and hardness properties of Ti-6Al-4V and may therefore potentially broaden the scope of application and performance of Ti-based materials in critical applications; particularly where wear and friction are critical concerns.