Neutron diffraction and finite element analysis of the residual stress distribution of copper processed by equal-channel angular pressing

Residual stress remaining after plastic deformation significantly affects the physical and chemical behaviors of materials. In this work, the residual stress distribution in Cu after single-pass equal-channel angular pressing (ECAP) was evaluated using neutron diffraction and the finite element method (FEM). The residual stress distributions simulated using the FEM are in good agreement with the experimental results measured using the neutron diffraction method. The workpiece had non-uniform distribution of residual stresses from bottom to top region of a rod specimen with circular cross-section. The axial residual stress in the top region of the workpiece was highly tensile; while it was only slightly tensile in the bottom region. On the other hand, the radial and hoop residual stresses were tensile in the bottom region, whereas they were compressive in the top region. Despite such non-uniformity of residual stresses, the middle region of the workpiece had relatively homogeneous tensile residual stresses. This investigation on the residual stress distribution in the ECAP-processed material provides a new window from which engineering problems in related with residual stress can be issued and solved.