Effects of strain rate on the microstructure and texture evolution of a TRIP-TWIP metastable austenitic stainless steel during bending

Microstructure evolution, deformation-induced martensitic transformation and texture evolution were investigated in a metastable austenitic stainless steel during bending under various strain rates ranging from έ = 10–5 s−1 to 10–2 s−1. Electron backscattering diffraction was used to track microstructure and texture evolution. With increasing the strain rate up to 10–2 s−1, the area fraction of the 60°/〈111〉 twin boundaries increased in the outer radius while this fraction reduced in the inner radius. The { 10 1 ¯ 2 } ⟨ 1 ¯ 011 ⟩ ε extension twins showed a sensitivity to the strain rate such that with the increasing strain rate, their fraction declined in the inner and outer radii. The mean kernel average misorientation markedly increased with increasing the strain rate with higher values for the outer radius compared to its corresponding inner radius. With increasing the strain rate, intensities of texture components were strengthened in austenite, ɛ- and α′ -martensite. The uncommon { h 11 } ⟨ 1 / h , 1 , 2 ⟩ -fibre was spotted at the strain rate of 10–5 s−1, while with increasing the strain rate up to 10–2 s−1, intensities around the fibre were weakened. Graphical abstract: [Figure not available: see fulltext.]