529 レーザーピーニング処理面における第二種ひずみの発生(OS5(1) 放射光,中性子,X線による材料強度の評価)

In this study, the intergranular effect generated in a laser peened surface of a ferritic steel was evaluated using neutron diffraction. The residual stress distribution from the surface to 1mm depth was obtained by the strain distributions measured using the 110, 200 and 211 reflections. The residual stress distributions derived from the strains of the 110 and 211 reflections were good agreement, while that of the 200 reflection, which is sensitive to the intergranular effect, indicated larger compressive stress by 100MPa to 200MPa in the surface layer until 0.8mm depth from the surface. It is probably intergranular effect, so that the residual stress measurement with consideration of the intergranular effect may be required to evaluate the residual stress generated in the surface layer of the surface treated sample such as the laser peening, the shot peening and so on.