Grain boundary character distributions of type-304 stainless steel cold-rolled and then annealed at 1173K were analyzed by electron back-scattering diffraction. The results showed that low strains (6 to 10%) followed by long-term annealing (24 to 96h) resulted in a grain boundary character distribution containing a high fraction of Σ9 and Σ27 boundaries. The ratio of fraction summation of Σ9 and Σ27 boundaries (fΣ9+Σ27) to the fraction of Σ3 boundaries (fΣ3), i.e. fΣ9+Σ27/fΣ3, reached 0.14 for the specimen strained by 6% and annealed at 1173K for 96h. The connectivity of general high-angle grain boundary network was interrupted significantly by Σ3n (n = 1 to 3) boundaries (special boundaries). However, intermediate strain (20 to 50%) followed by long-time annealing introduced a grain boundary character distribution of a much lower fraction of Σ9 and Σ27 boundaries, the value of fΣ9+Σ27/fΣ3 was only around 0.03 and the connectivity of high-angle grain boundary network was not interrupted basically. Additionally, it was observed that a fair number of clusters consisting of Σ3–Σ9–Σ27 boundaries were developed in the process of low strain followed by long-time annealing (96h), while the same phenomenon was hardly seen in the process of intermediate strain followed by long-time annealing.

Twin-Induced Grain Boundary Engineering in 304 Stainless Steel. X.Fang, K.Zhang, H.Guo, W.Wang, B.Zhou: Materials Science and Engineering A, 2008, 487[1-2], 7-13