Influence of Carbon Content on Tensile Properties of Pure High Manganese Austenitic Steel

Abstract

The tensile properties of high manganese austenitic steels with a carbon content ranging from 0.79 to 1.28 wt.% were tested. X-ray diffraction, electron backscattering diffraction, transmission electron microscopy, and optical microscopy were used to observe the microstructures after tensile deformation. Results showed that the strength and plasticity of these high manganese austenitic steels increased with increasing carbon content. The tensile strength and elongation of the 130Mn11 steel reached 941 MPa and 38.2%, respectively. The 0.79% carbon-containing steel (80Mn11) formed the most deformation twins at the same strain because of the low stacking fault energy, which resulted in a high strain hardening rate. However, this high strain hardening rate was unsustainable, and the tensile properties of the 80Mn11 steel were the worst, with its tensile strength nearly 200 MPa lower than that of the 130Mn11 steel. In the case of the 1.28% carbon-containing steel (130Mn11), the relatively low density of deformation twins, the large number of dislocations, and intensified DSA effect made the steel display a moderate strain hardening rate, which facilitated the sustainability of deformation, and an excellent combination of strength and plasticity were obtained.