Prediction of deformation textures in asymmetric rolling of aluminium alloys

Asymmetric cold rolling (ASR) has been shown to have potential to improve the formability of aluminium sheet alloys in deep drawing by increasing the normal plastic anisotropy, mainly as a result of the additional shear strains it imposes and the consequent alteration of the crystallographic texture. It is generally found that the process produces shear strains that vary across the sheet thickness, resulting in heterogeneity of the texture and related properties. While it may be a typical design goal of conventional rolling processes to maximise product homogeneity, it is not yet understood to what degree, in the context of the unique texture control possible with ASR, homogeneity and formability are conflicting objectives. Research describing the influence of process parameters on these phenomena has been reported for particular experimental ASR configurations, but a more broad exploration of the process window by parametric study has yet to be presented, in particular in the context of anisotropic plasticity and control of texture evolution. The work presented here addresses this need via a parametric study employing anisotropic FE and multi-scale material modelling to provide insight into the link between the process parameters and the final texture. It is demonstrated that a range of textures and degrees of homogeneity are achievable for aluminium with this innovative process, with potential for improving the formability in deep drawing. The results of this work are used in a subsequent analysis (presented separately) of the texture change during annealing, and an assessment of the resulting forming properties and impact of texture gradients via simulations of tensile tests.status: publishe