Modulating Mechanical Properties of Fe-0.35C-3.2Al-5Mn Hot-Rolled Steel by Combining Twinning-Induced Plasticity plus Transformation-Induced Plasticity Effect

The microstructures and mechanical properties of Fe-0.35C-3.2Al-5Mn (in wt%, same later) hot-rolled medium-manganese steels are systematically investigated. The results show that ultrafine-grained duplex phases with bimodal morphologies of lath and equiaxed are obtained with intercritical annealing at 750 degrees C for 1 h, along with ultimate tensile strength of 950 MPa and total elongation of 71.2%, attributed to the dislocation slip and deformation of ferrite matrix, accompanied by the synergetic twinning of retained austenite plus transformation of retained austenite to martensite. The newly developed medium-manganese steels, which exhibit an excellent product of ultimate tensile strength and total elongation of 67.6 GPa center dot%, demonstrate great practical applications.

Automated summary

The microstructures and mechanical properties of hot-rolled Fe-0.35C-3.2Al-5Mn medium-manganese steels were systematically investigated, showing that ultrafine-grained duplex phases with bimodal morphologies can be obtained through intercritical annealing, resulting in high ultimate tensile strength and total elongation. The newly developed medium-manganese steels demonstrate great practical applications due to their excellent combination of mechanical properties.