Abstract
This study investigated thermal and mechanical relaxation of residual stresses and fatigue strength following hot-corrosion of single-crystal CMSX-4 laser peened (LP) and a cyclic LP plus annealing (LP+TME) processes. Stress measurements showed LP plastic penetration exceeded shot peening depth by a factor of 25. Specimens were exposed to sulphate corrosives at 700°C for 300 hours and then fatigue tested. Five non-LP specimens failed in low cycle whereas three LP samples achieved multi-million-cycle runout, indicating consistent large benefit by laser peening. Fatigue strength tests achieved improvement of 2:1. Post-fatigue RS measurement showed 5 mm depth eigenstress remaining in an LP specimen.
Session
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