Residual stresses of a copper bicrystal were measured by X-ray diffraction and synchrotron
radiation. A copper bicrystal specimen with a 90-degree tilt boundary was fabricated by the Brigdman
technique. After the plastic extension of 30%, kink bands developed in a deformed matrix along the
grain boundary. In this study, we focused on the residual stress distribution along the transverse direction
of the specimen surface and the residual stresses in deformed matrix and kink band near the grain
boundary. Residual stresses were evaluated by the X-ray single crystal measurement method.
Stereographic projections were used to determine crystal orientations of deformed regions. It was found
that crystal orientations were different between the deformed matrix and the kink band. Residual stresses
in the direction along the grain boundary were compressive in the vicinity of the boundary and tensile in
the region apart from the boundary. Residual stresses in the kink band were large in compression in
compared with those in the deformation matrix. The difference in the results between X-rays and
synchrotron radiation suggests that there is a depth variation in the deformation and therefore the residual
stress development.
Transverse fatigue behaviour and residual stress analyses of double sided FSW aluminium alloy joints