Deformation mechanism map
Definition:A deformation mechanism map exhibits the chemical concentration domains where the different deformation mechanisms may occur during deformation of high Mn steels.
Explanation:During deformation, high Mn steels develop extraordinary service properties by effective deformation mechanisms, i.e. transformation induced plasticity (→TRIP), twinning induced plasticity (→TWIP), and microband induced plasticity (→MBIP). The properties of high Mn austenitic steels are strongly influenced by the stacking fault energy (→SFE). The SFE controls the equilibrium distance between partial dislocations in face-centred cubic (→fcc) metals and the activation of possible deformation mechanisms. Therefore, the deformation mechanisms in high Mn steels can be predicted based on the thermodynamic calculation of SFE maps. Accordingly, the influence of the alloy composition and temperature on the SFE and thus deformation mechanisms can be predicted.
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Three dimension composition-dependent SFE map of Fe-Mn-Al-C steel at 300K [1].
SFB-Link:Within SFB 761, a deformation mechanism map is used to predict the deformation mechanisms of high Mn steels and to further design the high Mn steels in Fe-Mn-C and Fe-Mn-Al-C systems. Based on the mechanism maps, the effect of alloy compostion and the temperature on SFE and the deformation mechanisms in high Mn steels are predicted.
References:[1] W. Song, T. Ingendahl and W. Bleck, Control of Strain Hardening Behavior in High-Mn Austenitic Steels. Acta Metallurgica Sinica (English Letters), 2014, 27(3), 546-556.