Effects of Cold Rolling on the Microstructure and Properties of Al/TiB2 Laminated Composites Fabricated by Accumulative Roll Bonding

Al/TiB₂ aluminum alloy laminates were fabricated using a combination of accumulative roll bonding (ARB) and cold rolling processes. The Al/TiB₂ interface and microstructure were meticulously characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical properties of the laminates were assessed through tensile testing. The experimental results demonstrate that with an increasing cold rolling reduction, a laminated composite sheet with a nanocrystalline structure was successfully produced. The critical strain for the onset of plastic instability was also investigated. The findings indicate that as the cold rolling reduction increases, severe necking occurs in the Al12Zn2.2Mg1.7Cu3TiB₂ layer. At a reduction of 80%, the necking region approaches fracture. Tensile results reveal that this pronounced necking has a detrimental effect on the strength of the laminate. It is proposed that the plastic instability originates from shear bands, and the mechanical property mismatch between the constituent layers is identified as the primary reason for the localized preferential deformation.