Effect of Traverse Rate in Ultrasonic Water Jet Peening on Surface Properties of Wrought Ti-6Al-4V

Abstract

Ti-6Al-4V is a popular alloy employed in numerous industrial applications. However, it exhibits poor wear resistance that leads to galling, seizure, and generation of wear debris. Surface modification techniques are commonly used to enhance the surface properties of materials. Ultrasonically pulsed water jet (UPWJ) peening is a relatively new technology that may possibly improve the surface properties of materials without excessive plastic deformation, detrimental thermal effects, or surface contamination. However, the influence of UPWJ peening parameters on the surface properties and wear resistance of titanium alloys is largely unknown. In this study, wrought Ti-6Al-4V was subjected to UPWJ peening at varying traverse speeds. The surfaces of the unpeened and peened wrought material were characterized by measurement and analysis of their surface roughness and scratch hardness through use of SEM and CLSM. Reciprocating wear tests were conducted on unpeened and peened wrought Ti-6Al-4V, and the wear tracks were analysed with SEM, CLSM, and EDS. It was found that UPWJ peening resulted in higher surface roughness than the unpeened material, although this was especially evident at low traverse speeds. Low traverse speeds also resulted in lower scratch hardness, although the scratch hardness was improved at higher traverse speeds. It was observed that UPWJ was detrimental to the wear resistance of the Ti-6Al-4V. At low traverse speeds, the material was highly susceptible to adhesive wear. At high traverse speeds, the material was found to experience an increased amount of abrasive wear.