Outstanding mechanical properties of high-pressure torsion processed multiscale TWIP-cored three layer steel sheet

Abstract

Three layer steel sheets composed of a twinning-induced plasticity (TWIP) steel core and two interstitial free (IF) steel sheath layers are processed by high-pressure torsion (HPT) up to 1 turn under an applied pressure of 6 GPa. The HPT-processed layered sheets demonstrate extraordinarily enhanced mechanical properties, showing high strength as well as very good ductility. Experimental studies reveal that the improvement of the mechanical properties originates from inhomogeneous strain imposed during HPT process and two distinct hardening mechanisms of each layer: grain boundary hardening of the IF steel and deformation-twinning-induced hardening of the TWIP steel. (C) 2016 Elsevier Ltd. All rights reserved.