Synergistic improving fretting fatigue resistance of Ti alloy at elevated temperature by duplex surface modification

The 0Cr18Ni9 film was deposited on Ti 811 titanium alloy surface by ion-beam-enhanced deposition (IBED). The composition distribution, bonding strength, hardness and the wear resistance of the film were investigated. Shot peening was introduced to post treat the modified surface in order to synergistically improve the fretting fatigue resistance of Ti alloy. The results indicate that IBED can prepare 0Cr18Ni9 film with high density, small grain size, low void radio and high bonding strength. Thus the hardness, wear resistance and fretting fatigue resistance of Ti 811 alloy are increased remarkably. Compared with shot peening treatment or ion-beam-enhanced deposition coating alone, the titanium alloy after IBED 0Cr18Ni9 combined shot peening shows high fretting fatigue resistance at elevated temperature of 350°C. This is due to the synergistic effect of the high wear resistance of the film surface and the residual compressive stress induced by shot peening.