The effect of different shot peening intensities on fatigue life of AW 7075 aluminium alloy

In this study the effect of different shot peening intensities, from very light peening with ceramic beads to severe shot peening with high coverage, on the fatigue life of aircraft AW 7075 aluminium alloy was investigated. Results were discussed in means of surface roughness, character of deformed surface layer and residual stress profile measured by XRD methods. Light peening intensity creates high and shallow compression residual stress field in the subsurface layers of material and increases the fatigue life of studied alloy. Increasing the peening intensity increases the depth of residual stress field, however the surface damage created by impact of shots at high velocity causes significant surface damage and rapidly degrade the fatigue properties of AW 7075 aluminium alloy