Relaxation behavior of peening residual stress under mechanical loading investigated by neutron diffraction

Akita, Koichi; Hayashi, Kengo*; Takeda, Kazuya*; Sano, Yuji*; Oya, Shinichi*

Relaxation process of peening residual stress under mechanical loading was investigated by neutron stress measurement method. Relaxation of the surface compressive residual stress was started before the stress of the surface layer reached the yield stress, which would be caused by the re-distribution of the residual stress due to the plastic deformation of the center region. Therefore, the understanding of the magnitude of balancing tensile residual stress is important to evaluate the relaxation of the surface compressive residual stress against tensile applied stress.