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

TL;DR

Cold rolling affects the microstructure and strength of Al/TiB2 laminated composites, causing necking and reducing strength due to layer mismatch.

Contribution

The study identifies the role of mechanical mismatch and shear bands in plastic instability during cold rolling of Al/TiB2 laminates.

Findings

Cold rolling with 80% reduction produces a nanocrystalline structure in Al/TiB2 laminates.

Severe necking occurs in the Al12Zn2.2Mg1.7Cu3TiB2 layer at high reductions, approaching fracture.

Localized deformation is caused by mechanical property mismatch between layers.

Abstract

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.

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