Substructures and internal stresses developed under warm severe deformation of austenitic stainless steel

The strain-induced grain evolution taking place in a 304 type austenitic stainless steel under severe warm deformation is studied in multipass compression at a temperature of 873 K with changing of the loading direction in 90° in every pass. The effects of strain-induced grain boundaries on the internal stresses and the related lattice distortions evolved in these grain interiors are discussed. These fine grains are characterized by high lattice curvatures irrespective of lowered dislocation densities. High internal stresses is explained by considering the junction distortions developed at non-equilibrium boundaries under severe plastic deformation, resulting in the decrease in dislocation densities evolved in fine grain interiors.