Development of Σ3n CSL boundaries in austenitic stainless steels subjected to large strain deformation and annealing

The development of annealing twins was studied in chromium-nickel austenitic stainless steels subjected to cold or warm working. The annealing behavior can be characterized by an austenite reversal, recrystallization, and grain growth, depending on the deformation microstructures. The grain coarsening during recrystallization followed by a grain growth was accompanied by the development of twin-related Sigma 3(n) CSL boundaries. The fraction of Sigma 3(n) CSL boundaries and their density are defined by a unique parameter that is a relative change in the grain size, i.e., a ratio of the annealed grain size to that one evolved by preceding plastic working (D/D-0). The fraction of Sigma 3(n) CSL boundaries rapidly increased at early stage of recrystallization and grain growth while the ratio of D/D-0 attained 5. Then, the rate of increase in the fraction of Sigma 3(n) CSL boundaries slowed down significantly during further grain coarsening. On the other hand, the density of Sigma 3(n) CSL boundaries increased to its maximum at a ratio of D/D-0 about 2.5 followed by a gradual decrease during subsequent grain growth.