Microstructure and texture characteristics of the metastable Fe-21Mn-3Si-3Al alloy after cold deformation

Cast Fe-21.2 Mn-2.99 Si-2.73 Al-0.02 wt.% C alloy ingot was homogenized at 1150 °C, hot-rolled at starting temperature 1000 °C, solution treated at 1150 °C for 1 h and cold-rolled to 56% thickness reduction. Metallographic and X-ray diffraction studies revealed that, for small degrees of deformation, ε martensite had nucleated within numerous stacking faults. EBSD analysis showed that α′ martensite also formed within the ε plates. Plastic deformation occurred by mechanical twinning and martensitic transformations, both γ → ε and γ → ε → α′ (TWIP and TRIP effect), with the Burgers (Shoji-Nishiyama) {0 0 0 1}ε||{1 1 1}γ, 〈1 1 2 0〉 ε || 〈1 1 0〉 γ and Kurdjumov-Sachs {1 1 1}γ||{1 1 0}α, 〈1 1 0〉 γ||〈1 1 1〉 α relations between the austenite (γ), and martensite (ε and α′).