The Role of Interfaces on the Deformation Mechanisms in Bimodal Al Laminates Produced by Accumulative Roll Bonding

Laminated metallic materials with an ultrafine‐grained (UFG) microstructure can easily be produced by accumulative roll bonding (ARB). Combining two different Al alloys, commercially pure (CP) and high‐purity (HP) aluminum, a layerwise bimodal microstructure is formed, where the CP layers consist of ultrafine grains whereas the HP layers show large grains as these layers undergo dynamic recrystallization during rolling. By applying different numbers of ARB passes and in addition by applying a subsequent heat treatment, the microstructure of the laminate can be changed significantly. Thus, different types of interfaces, specifically the grain boundaries of the ultrafine grains and the interfaces between the different layers of CP and HP aluminum are dominating the deformation behavior and the mechanical properties of these laminates. This article addresses how the UFG boundaries and the layer interfaces affect the mechanical properties under monotonic and cyclic loading, and discusses the relevant deformation mechanisms. The deformation behavior of layerwise bimodal laminated metallic composites (LMCs) is investigated. These LMCs are produced by accumulative roll bonding (ARB) combining commercially pure (CP) and high‐purity (HP) aluminum alloys. The deformation behavior of the LMCs changes significantly, when the layer thickness equals the grain size, as the deformation behavior becomes then dominated by the layer interfaces.