FRETTING FATIGUE BEHAVIOR of COMBINED PLASMA ZIRCONIUMING and SHOT PEENING on Ti6Al4V ALLOY

Low wear resistance and high sensitivity to fretting fatigue (FF) damage limit the application of titanium alloys. In order to improve its wear resistance, surface plasma Zirconium (Zr) alloying is a candidate through solution strengthening with its property of infinite solid solution with α-Ti and β-Ti. In this work, the plasma Zr metallurgy technique was used to improve the FF resistance of Ti6Al4V alloy combined with shot peening (SP), which is different from the combined treatments of the surface modification with high hardness and SP, and may explain the impacts of ductility and strength in improving FF resistance. The results indicate that the Zr metallurgy layer is composed of a Zr-Ti solid solution with low surface hardness and density, which induce the reduction of the fretting wear (FW) resistance and FF resistance of the Ti6Al4V alloy. Instead, when SP was used as the post treatment, the FW and FF behavior of the titanium alloy were increased obviously after prior plasma Zr metallurgy, especially to high cycle fatigue. This indicates that residual stress introduced by SP is beneficial for improving both FW and resistance.