Σ3n special boundary distributions in the cold-rolled and annealed 304 stainless steel

Grain boundary character distributions (GBCD) in the 304 stainless steel cold rolled and then annealed at 1173 K were analyzed by electron back scatter diffraction (EBSD). The results showed that under low strain (about 6%) followed by long-time annealing (24-96 h) the special boundaries with a higher fraction of Sigma 3(n) (n=1, 2, 3) boundaries appeared, and the connectivity of general high angle grain boundary (HAB) network was interrupted by Sigma 9 and Sigma 27 segments. Incoherent and coherent Sigma 3 boundaries were identified by single-section trace analysis method, which showed that the major part of Sigma 3 boundaries was incoherent one in the optimized GBCD. Further discussion pointed out that the migration and interaction of incoherent Sigma 3 boundaries are relative to the twin-induced GBCD optimization.