Deformation Structure and Texture Transformations in Twinned Fcc Metals: Critical Role of Micro- and Macro- Scale Shear Bands

Abstract

Microstructure and texture development in twinned fcc metals is investigated in order to characterize the influence of micro- and macro-scale brass-type shear bands (SB) on structural and textural changes at large deformations. TEM and SEM analyses are focused on bands developed by plane strain compression in twinned C{112}<111> oriented single crystals. The proposed crystallographic model of the shear banding phenomenon refers to the idea of local lattice reorientation within narrow areas. Most of these rotations occur around the TD||<110> axis with significant further rotations about <112> poles. These two rotations explain the influence of SB’s on the formation of Goss{110}<001> and brass{110}<112>-S{123}<634> texture components clearly observed in highly deformed low SFE metals. At high deformations symmetrically equivalent crystal lattice rotations inside narrow areas lead to the formation of positive and negative macroscopic SBs.