Modeling of Flow Stress and Micro-structural Variations in Stain Induced Dynamic Transformation of Low Carbon Steel by Hot Torsion Deformation

摘要

The relationships between flow stress curve and microstructure evolution of strain induced dynamic phase transformation (SIDT) using low carbon steel (0.22 wt. percent) were quantitatively investigated. The deformation was carried out at just above Ar_3 temperature (710 deg C) as a function of strain rate (0.01-5/sec). The softening process of SIDT was well modeled based on Avrami and constitutive equations similar to the existing dynamic recrystallization process. However, the calculated results differed from the experimental curve as decreased the strain rate under 0.2/sec, this is due to that the dynamic transformation from austenite to ferrite is not completed by lower deformation stored energy.