Effects of Annealing Temperature on the Microstructure and Mechanical Properties of Warm‐Rolled Advanced High‐Strength Twinning‐Induced Plasticity Steel

This study systematically investigates the influence of annealing temperature (400–900°C) on the microstructural evolution and mechanical properties of a warm‐rolled (80% reduction) twinning‐induced plasticity (TWIP) steel with the composition of Fe‐17.76 Mn‐1.65Al‐0.65C‐0.46Si (wt%), a material prized for its strength‐ductility combination in mining applications. With increasing temperature, the microstructure underwent sequential recovery and recrystallization, leading to a significant reduction in dislocation density and the precipitation of κ‐carbides. Tensile strength progressively decreased from 2013.5 MPa to 1222.9 MPa, while elongation markedly increased from 5.4% to 46.7%. Annealing at 700°C promoted optimal interactions between residual deformation twins and dislocations, balancing strength and ductility. Upon annealing at 500°C, κ‐carbides preferentially precipitated in high‐density shear bands. As the temperature increased, these carbides evolved from interconnected, elongated structures into fine, uniformly distributed particles, significantly enhancing ductility. Further heating promoted carbide dissolution alongside austenite recovery and recrystallization, forming a lamellar heterogeneous structure. This work confirms annealing temperature as a critical parameter for optimizing the strength–ductility synergy in TWIP steels, offering valuable guidance for process design.