A crystal plasticity FEM study on macro- and micro-subdivision of an aluminium single crystal after multi-pass unidirectional rolling, reverse rolling and accumulative roll-bonding

The deformation of accumulative roll-bonding (ARB) is complicated due to repeated cutting, stacking and roll-bonding. In this report, the deformation of multi-pass unidirectional and reverse rolling was first investigated, and then the investigation was extended to ARB. Aluminium single crystal {1 0 0}<0 0 1> (Cube) was chosen as the starting material, and crystal plasticity finite element method was used. The predictions after unidirectional and reverse rolling were validated by experimental observations. Macroscopic subdivision occurred by forming matrix bands through the thickness. It was found that the subdivision at the macroscopic scale was respectively amplified and destroyed after unidirectional rolling and reverse rolling. After ARB, macroscopic subdivision was partially amplified and destroyed through the thickness. Another modelling technique, Submodel, was adopted to highly increase the mesh resolution in selected smaller regions, by which micro-subdivision was successfully captured and verified by experimental results. Similar to the macro-subdivision, the micro-subdivision was respectively strengthened and disrupted after unidirectional rolling and reverse rolling. At both the macro- and micro-scale, the crystal rotation, slip activity and shear strain alternate their directions through the thickness, and the correlation between them three was investigated based on the crystal plasticity theory. Finally, the effect of rolling direction to texture, microstructure and mechanical properties was discussed.