Effect of Nb and Mo on the hot ductility behavior of a high-manganese austenitic Fe-21Mn-1.3Al-1.5Si-0.5C TWIP steel

This research work studies the influence of single microalloying elements (Nb and Mo) and the solidification route on the hot ductility behavior of a high-manganese austenitic Twinning Induced Plasticity (TWIP) steel. For this purpose uniaxial hot tensile tests in the temperature range of 700-1100 °C under a constant true strain rate (10−3 s−1) were carried out to evaluate the hot ductility as a function of reduction in area (%RA). In general, results revealed a beneficial influence of Nb and Mo additions to TWIP steels on the hot ductility behavior, particularly in the intermediate temperature range of 800-900 °C, where the reduction of area (RA) value can be as high as 73%. The hot ductility behavior of the present TWIP steels is discussed in terms of solid-solution strengthening, solute drag phenomenon, dynamic recrystallization (DRX) and grain boundary precipitation. Ductile fracture type was recognized as the material failure surface containing many dimples in almost all the studied cases.