Unveiling slip/nanotwin/nano shear band deformation mechanisms at the copper side in a roll-welded aluminum/copper couple

Abstract

In this study, the co-deformation behavior of Cu in an Al-Cu couple was evaluated. It is observed that slip, twinning, and partial shear banding were responsible for deformation in Cu during cold welding. For characterization purposes, transmission electron microscopy (TEM) was employed to detect deformation mechanisms after the rolling. It was demonstrated that the formation of nanotwins could have evidently influenced the microstructure of the Cu side. The junction of twin/twin, twin/slip, and twin/shear bands was another major observation and confirmed complex microstructure during rolling. Also, the resulting co-deformation has a noticeable effect on microhardness as compared to the aluminum side. Moreover, the textural investigations were conducted by the X-ray diffraction (XRD) and electron back-scattered diffraction (EBSD) methods after rolling. Textural investigations exhibited a transition from Cube to rolling texture (mainly Brass) and shear (Rotated Cube) textures. For validation of shear deformation texture in Al-Cu, a finite element method (FEM) was employed, and approved experimental textural studies regarding shear texture formation.