Formation Mechanism of Residual Stress Field Induced by Surface Strengthening Process

The formation of the residual stress field that accompanies severe plastic deformation is analyzed in view of the crystal structure evolution and mechanical response of the material. The conclusion drawn is that elastic release is the fundamental cause of the residual compressive stress field in the near-surface layer, while the residual tensile stress field in the deep region is attributed to load conservation. The elastic strain, which is embodied by the offset of a metal atom to the equilibrium position of the lattice, varies with the depth of the material owing to the differentiated effects of elastic release and load conservation.