Effect of deformation induced transformation of ɛ-martensite on ductility enhancement in a Fe-12 Mn steel at cryogenic temperatures

Interpretation of cryogenic-temperature Charpy impact toughness by microstructural evolution of dynamically compressed specimens in austenitic 0.4C–(22–26)Mn steels

“…They are formed along the [2-1-10] direction in a lath shape inside prior austenite nanograins elongated by the dynamic compressive deformation, and show their own diffraction patterns. Nanocell structures and a 0 -martensite phases, which are known to be formed by way of e-martensite phases [18,35], are not found. In the 24Mn and 26Mn steels, nanocell structures are well formed as shown in Figs.…”

Effects of Annealing Treatment Prior to Cold Rolling on Delayed Fracture Properties in Ferrite-Austenite Duplex Lightweight Steels

“…[45] When the tensile loading directions are varied, like in the present study, Schmid factor plays an important role in austenite stability. [46] Considering that the martensitic transformation is triggered by the supply of strain energy as a consequence of dislocation pile-ups at strong barriers such as grain boundaries, [47][48][49] the martensitic transformation preferentially occurs in regions having high resolved shear stresses, i.e., high Schmid factors, even in the same grain size and composition conditions. Figures 11(a) and (b) show EBSD Schmid factor maps of austenite in the 0, 45, and 90 deg directions during the cup formation.…”

Interpretation of cryogenic-temperature Charpy fracture initiation and propagation energies by microstructural evolution occurring during dynamic compressive test of austenitic Fe–(0.4,1.0)C–18Mn steels

“…Efforts have also been made to achieve an excellent combination of high strength and toughness by using deformation mechanisms [1][2][3][4][5][6][7][8][9]. These mechanisms are mainly changed by stacking fault energy (SFE), and the SFE generally increases with increasing C and Mn contents [5][6][7][8][9][10][11][12][13][14].…”

“…These mechanisms are mainly changed by stacking fault energy (SFE), and the SFE generally increases with increasing C and Mn contents [5][6][7][8][9][10][11][12][13][14]. TWinning Induced Plasticity (TWIP) mechanism activates in the SFE range of 20-50 mJ/m 2 [5,6].…”

“…Mechanical twins beneficially work for the grain refinement [7,8], thereby leading to the simultaneous improvement of strength, ductility, and toughness [9][10][11][12][13][14]. As the temperature decreases down to cryogenic temperature, deformation mechanisms such as TRansformation Induced Plasticity (TRIP) are activated by the continuously decreased SFE [7][8][9][10][11][12][13][14]. The change of deformation mechanism induces the formation of various microstructures such as refined austenite, martensite, and mechanical twin, which greatly influences the strength, ductility, and toughness.…”