Effect of multiple laser shock peening without coating on residual stress distribution and high temperature dry sliding wear behaviour of Ti-6Al-4 V alloy

•Residual stress distribution, microhardness, microstructure and surface roughness after laser peened Ti-6Al-4 V was discussed.•High temperature dry sliding wear behaviour of laser peened Ti-6Al-4 V alloy was investigated.•Wear resistance was improved after laser peening process at both ambient and high temperature. The effect of laser peening without coating (LPwC) on the tribological behaviour of Ti-6Al-4 V alloy at ambient (28 °C) and elevated temperatures (300 °C) was investigated. The influence of residual stress, microhardness, microstructure, and surface roughness is discussed. The samples show maximum compressive residual stress of –550 MPa and hardness of 395 HV after peening. Electron back scattered diffraction (EBSD) analysis shows the reduction in average grain size and increase in Low-angle grain boundaries fraction for LPwC samples compared to unpeened samples. The average friction coefficient and wear volume loss were found to be significantly reduced after the laser peening process. At ambient temperature, a severe abrasive wear mechanism was identified in unpeened samples, and a mild abrasive wear mechanism was observed for LPwC samples. LPwC samples show a relatively smooth worn surface than the unpeened samples, resulting in reduced wear volume loss of 30, 24.75 and 17.08 % than the unpeened samples at 10, 20 and 30 N loading conditions. At elevated temperature, unpeened samples show severe abrasive wear and mild oxidative wear mechanism, whereas, in LPwC samples, the wear mechanism shifted from severe abrasive to oxidative and mild abrasive wear resulting in reduced wear volume loss of 30.3, 19.58 and 13.43 % compared to unpeened samples at 10, 20 and 30 N loading condition respectively.