Role of shear in interface formation of aluminium-steel multilayered composite sheets

Aluminium – Interstitial Free (IF) steel multilayered composite sheets with different volume fractions of aluminium were produced by accumulative roll bonding (ARB) and Asymmetric Accumulative Roll Bonding (AARB). The IF steel and Al alloy (AA1050) sheets were stacked in a sandwich like structure and roll-bonded by two passes with varying roll diameter ratios (d_r) equal to 1 and 2 for ARB and AARB processes, respectively. This work focused on a study of the effect of shear strain mode on the formation of the interface zone. The interface zone thickness, which formed by intermixing and diffusion, was characterised by different techniques including STEM-EDS line scan, HRTEM and Atom Probe. Furthermore, finite element simulations of both processes were conducted to determine the level of shear strain at the interfaces. It was demonstrated that the width of the interface zone directly correlates with the magnitude of shear strain and architecture of the hybrid material.