Investigation on the surface and near-surface characteristics of Ti–2.5Cu after various mechanical surface treatments

As a result of the variety of mechanical surface treatments, studies of surface and near-surface characteristics are becoming increasingly important in a variety of industrial fields. This is to achieve more gains by balancing between optimum conditions and costs. In the present study, shot peening (SP), ball-burnishing (BB), laser shock peening (LSP) and ultrasonic shot peening (USP) processes were performed on the α-titanium alloy Ti–2.5Cu after two different heat treatments. The influence of such surface treatments on the surface and near-surface characteristics, such as residual stress, work hardening or dislocation density and surface roughness, was studied. The depth profiles of residual stress and full width at half maximum (FWHM) were obtained by using energy-dispersive X-ray diffraction. Results show that the BB process produced the highest and deepest maximum residual stress and LSP produced the lowest work hardening close to the surface.