Abstract
The effects of cavitation peening (CP) and shot peening (SP) on bending fatigue strengths of an aluminum alloy (A7075-T6) specimen with an artificial semi-circular slit were investigated The bending fatigue test specimens with small semi-circular slit were subjected to CP and SR Bending fatigue tests were conducted on the specimens to determine the fatigue strength and the depth of the semi-circular slit that can be rendered harmless by CP and SR It was found that the fatigue strength increased and a semi-circular slit less than 0.2 mm and 0.1 mm in depth was rendered harmless by CP and SP, respectively. The depth of a semi-circular slit that can be rendered harmless by CP and SP was estimated based on fracture mechanics assuming that the semi-circular slit was equivalent to a semi-circular crack The prediction results were almost consistent with the experimental results. These results indicated that the distribution of compressive residual stress is a controlling factor of the depth of the semi-circular slit that can be rendered harmless by peening.
