Hot Deformation Behaviors of Fe-3QMn-3Si-3Al TWIP Steel during Compression at Elevated Temperature and Strain Rate

摘要

The hot deformation behavior of twinning-induced plasticity (TWIP) steel was investigated at 973-1373 K and strain rates of 0.01-20 s~(-1) by hot-compression experiments performed on a Gleeble-3800 thermo-simulation test system. Microstructural evolution during recrystallization in the hot deformed TWIP steels was investigated by metallurgical analysis. The hot-flow behavior can be represented by a Zener-Hollomon parameter in the hyperbolic-sine equation. The hot-deformation activation energy is 436.813 kJ mol~(-1). Deformation bands are initially generated in the deformed austenitic grains during the dynamic recrystallization (DRX) of TWIP steel. With increasing temperature, the recrystallized grains emerge at the boundary junctions after the disappearance of the deformation bands. Subsequently, they gradually spread along the austenitic boundaries and exhibit a necklace shape. The dynamic recrystallized grains continuously grow until they finally reach equilibrium. The DRX mechanism of TWIP steel is a boundary bulge mechanism. The optimum hot-working technology parameters (especially for rolling) for the TWIP steel is the deformation temperature range of 1223-1323 K, and strain rate range of 1-10 s~(-1).