Effect of manganese content on hot deformation behaviour of Fe–(20/27)Mn–4Al–0.3C non-magnetic steels

The influence of Mn content on flow behaviour and constitutive equations of Fe–(20/27)Mn–4Al–0.3C austenitic steels was investigated by uniaxial hot compression tests. The recrystallisation fraction was also measured using electron backscattered diffraction. Although dynamic recrystallisation is slightly delayed by the increased Mn content, the peak stress still has a pronounced decline especially during the deformation at relatively low temperature. The reason should be ascribed to the enhanced stacking fault energy, by which workhardening rate before the onset of dynamic recrystallisation is diminished significantly with the reinforced cross-slip process. The hot deformation activation energy is decreased under the condition of higher Mn addition, while the strain rate sensitivity of flow stress almost remains unchanged.