Stability of shot-peen residual stresses in an α + β titanium alloy

Shot-peen residual stress relaxation due to thermal exposure and fatigue loading was characterized in Ti–6Al–2Sn–4Zr–6Mo. Approximately 80% of the residual stresses were retained at 399 °C up to 100 h. Under fatigue loading close to yield stress, retention of residual stresses was approximately 85%, 70% and 50% at 260, 316 and 399 °C, respectively. Crack growth calculations demonstrate 1.5–5× benefit in life, even for partial credit for shot-peen residual stresses.