Stretchability and drawability of twinning-Induced plasticity steel-Cored layer steel sheets

In this work, the qualCONVERSION(0ities of sheet formability (i.e., stretchability and drawability), of twinning-induced plasticity (TWIP), steel-cored thr$ee-layer steel sheets were investigated in terms of tensile parameters (i.e., strain hardening exponent, strain rate sensitivity, normal anisotropy, mean R-value, and total elongation). The tensile parameters of TWIP steel-cored three-layer steel sheets follow the force-based rule of mixtures. The limit drawing ratio, the measure of drawability, of the three-layer steel sheet was proportional to the mean R-value and the strain rate sensitivity while the limit dome height (LDH), the measure of stretchability, could not be correlated with any tensile parameters. The LDH of the TWIP steel-cored layer sheet was superior to that of the single layer due to the inhibition of serration in the TWIP steel-core during the Erichsen test.