Probabilistic analysis of the effect of shot peening on the high and low cycle fatigue behaviors of AA 7050-T7451

Fatigue life reliability (best trade-off of fatigue life dispersion and mean values) depended on the tested Almen intensity and stress amplitudes. At high stress amplitude, cast steel shot S230 was the most reliable condition because of the smooth surface it induced. At low stress amplitude, peening with ceramic Z425 shots at an intensity of 8A was the most reliable condition, while it was the least reliable in high cycle fatigue. The fractography analysis, completed for every condition, revealed shot contamination on samples peened with Z425 shots at an intensity of 8A and tested at high stress amplitude, which could be responsible for the deterioration of the fatigue properties.