Evaluation of Mechanical Behavior and Surface Morphology of Shot-Peened Ti-6Al-4V Alloy

Abstract

The effects of shot peening (SP) on mechanical behavior and surface morphology of Ti-6Al-4V were investigated in detail. After SP, the uniformity of compressive residual stress (CRS) was analyzed. The CRS decreased as SP intensity increased because of the severe impact of shots. The CRS was enhanced from − 762.7 to − 795.5 MPa with an increase in SP intensity. The fatigue life was increased from 0.46 × 106 cycles to 8.10 × 106 cycles after SP when the loading amplitude was 610 MPa. This increase was mainly attributed to the enhancement of the crack initiation hindering and propagation by the high CRS and refined domain sizes. The results of surface morphology showed that the convexity and concave regions were generated after SP and the improvement in SP intensity aggravated the increase in roughness. Although the roughness increased after SP, it did not hinder the enhancement of fatigue lives, indicating that CRS played a leading role in the improvement in fatigue lives. Thus, the analysis and discussion revealed that SP was beneficial for the improvement of the surface mechanical behavior of titanium alloys.