Microstructural Evolution and Hot Deformation Behavior of Cu-Containing Twinning-Induced Plasticity Steel

Abstract

High manganese twinning-induced plasticity (TWIP) steels with excellent strength and plasticity have promising applications in automotive manufacturing, but limited corrosion resistance affects their further development. Alloying with Cu is a viable solution to improve corrosion resistance. However, there remains a paucity of research concerning the effect of Cu on the hot deformation behavior of TWIP steels. So, the investigation of the recrystallization behavior and microstructural evolution in Fe-23Mn-6Cr-3Al-0.2C-xCu (x = 0, 2.5) TWIP steels has been conducted using uniaxial hot compression test. The results reveal that Cu alloying exerts minimal influence on the high-temperatur flow behavior, with dynamic recrystallization emerging as the predominant softening mechanism in Cu-containing TWIP steels. However, owing to the drag effect of solute atoms, Cu alloying increases the activation energy for hot deformation and marginally reduces hot workability. Fine recrystallized grains in Cu-containing TWIP steels can be achieved by hot deformation at lower temperatures and strain rate regions. The recrystallization behavior of Cu-containing TWIP steels hot deformed at low temperatures and high strain rates is obviously inhibited by the increase of the activation energy and stacking fault energy, coupled with the hindering effect of Cu solute atoms clustered at grain boundaries on grain boundary migration.