Enhancement of Mechanical Properties of high-Mn TWIP Steel with Fast Heating process: Insights into Microstructural Evolution and Performance Optimization

Abstract

This study explores the impact of fast heating (FH) technique on the microstructural evolution of heavily cold-rolled TWIP steel, focusing on the temperature range of 1000-1200°C for a duration of 5 seconds. Utilizing a Gleeble 3600 simulator, FH experiments were characterized by rapid heating rates of 500°C/s and cooling rates of 400°C/s. The promoted microstructures were analyzed using Electron Backscatter Diffraction (EBSD), while mechanical properties were evaluated through microhardness measurements and uniaxial tensile tests. The results revealed that the FH process promotes a fully recrystallized microstructure. At 1000°C, this FH cycle yields an ultrafine-grained structure with an average grain size of approximately 2.5 µm, which synergistically enhances both tensile strength (750 MPa) and extreme ductility (105%). However, the FH cycle at 1200°C results in a coarser-grained structure with an average grain size of about 20 µm. This microstructure, while reducing tensile strength to 650 MPa, significantly increases ductility to 120%. These findings illustrate a valuable synergy between FH parameters and microstructural development, offering a strategic approach to optimizing the mechanical performance of TWIP steels.