Effect of unbalanced magnetron sputtering MoS₂/Ti composite films on the tribological properties and fretting fatigue behaviors of Ti811 alloy at elevated temperature

MoS₂/Ti composite films were prepared on Ti811 titanium alloy substrate by unbalanced magnetron sputtering (UBMS) method. The composition, bonding strength and hardness of the films were measured. The effect of the composite films on the tribological properties and fretting fatigue of Ti811 titanium alloy at 350°C were investigated. The results indicate that the MoS₂/Ti composite films prepared by UBMS technique had high density, small grain size, low void radio, and high bonding strength. The MoS₂/Ti composite films improved the resistance of wear and fretting fatigue of the Ti alloy due to excellent lubricating properties of the films at 350°C. The UBMS films on the titanium alloy after shot peening exhibited better fretting fatigue resistance than the UBMS films without shot peening did. The compressive residual stress on the shot peened surface relaxed during preparing the MoS₂/Ti composite films process, so they exhibited reduced fretting fatigue resistance.