Effect of laser shock peening on cylinder-on-flat torsional fretting wear resistance performance of titanium alloy

Torsional fretting wear is a commonly wear form in assemblies, while its inherent concealment and debris evolution make it difficult to study. Titanium alloy, widely used in aviation and aerospace, suffer from fretting wear under complex alternating load. In this paper, the effects of laser shock peening (LSP), fretting amplitude, and frequency on cylinder-on-flat torsional fretting wear of TC21 alloy was investigated. The friction torque and fretting loop were illustrated to identify the fretting regime. Results shown that LSP reconstructed surface morphology, increased surface roughness and hardness, meanwhile reduced the wear volume of titanium by more than 30 %. The fretting wear mechanisms varied with amplitude: lower amplitudes led to oxidation and adhesive wear, while higher amplitudes caused oxidation and abrasive wear. The results of wear volume shown that the influence of fretting frequency on wear was related to the difficulty of wear debris discharge.