High space-resolutive evaluation of subsurface stress distribution by strain scanning method with analyzer using high-energy synchrotron X-rays

Shobu, Takahisa  ; Mizuki, Junichiro; Suzuki, Kenji*; Akiniwa, Yoshiaki*; Tanaka, Keisuke*

The surface aberration effect in the strain scanning method with a Ge analyzer was examined using high-energy X-rays from the undulator synchrotron source. The use of a Ge (111) analyzer showed remarkable reduction of the surface aberration effect. However, there still existed the surface aberration for the very-near surface region from the surface to the depth of 50 micro meter. A correction method was proposed by taking into account of the effects of the divergence of the Ge analyzer, the mis-setting of the analyzer and the X-ray attenuation. The proposed correction method was very useful for eliminating the surface aberration effect. The correction method enables a high space-resolutive evaluation of the subsurface stress distribution. The method was successfully applied to the determination of the residual stress distribution of the shot-peened steel.