Effect of compressive residual stress on fatigue strength of aluminum alloy by laser peening

Takeda, Kazuya*; Oishi, Masayuki*; Akita, Koichi; Oya, Shinichi*; Sano, Kenji*; Saito, Toshiyuki*

Effects of compressive residual stress on fatigue strength on a laser peened aluminum alloy were investigated. The changes of the compressive residual stress were measured using X-ray diffraction. The residual stress was relaxed at the first loading cycle and after that the residual stress was almost kept until the final fracture. The number of fatigue cycles to failure could be predicted quantitatively if the compressive residual stress after the first loading cycle was estimated.