Influence of strength and residual stress on fretting wear and fatigue behavior of surface alloyed Ti6Al4V alloy

A metallurgical zirconium nitride (ZrN) layer and a zirconiuming (Zr) layer were fabricated using double glow metallurgy technique on Ti6Al4V alloy. The influence of strength and residual stress on fretting wear (FW) and fretting fatigue (FF) behavior of the Ti6Al4V alloy was studied. The surface microhardness of the composite ZrN and Zr layer is respectively 1775 and 380 HK0.1. The ZrN layer improves the FW resistance of the Ti6Al4V alloy, but reduces the FF resistance. The Zr layer reduces both the FW and FF resistance of the Ti6Al4V alloy. This is because that none surface layer without defects could be fabricated. By introducing the surface compressive residual stress, the FW resistance of both ZrN and Zr layers is improved; the FF resistance of both layers is strengthend to be greater than that of base materials. A reasonable surface residual stress across depth is a necessary requirement for improving the FF behavior of Ti6AL4V alloy. Reasonable surface strength is preferred for improving both FF and FW resistance on the priority of no reducing cracks or peels.