Texture development in the interfacial zone of Al/Cu bimetal cold roll-bonded for E-mobility

Cold roll-bonded Al/Cu bimetal has been widely used in heat sinks for main converters in E-mobility. The development of textures in the interfacial zone of cold roll-bonded Al/Cu bimetal was investigated with the help of orientation distribution function (ODF) analysis based on the FEG-SEM/EBSD technique. The present results show that the texture development of the cold-rolled Al strips can be represented by an α-fibre shift approaching the bonding interface. Cold rolling of Cu strips in the bonding zone splits Goss {1 1 0}<0 1 0> and increases the intensities of metastable T {1 1 2}<1 3 1> texture components. By approximating the bonding interface, T components dissolve and both α- and γ-fibre sharpen. The intensities of the approx. 40° <1 1 1> pair, Cu {1 1 2}<1 1 1> and RC {1 0 0}<0 1 1>, increase significantly. The strong bonding of the bimetal can be attributed to the strain-induced formation of ultrafine grains during severe plastic deformation at the bonding interface without recourse to concepts such as 'diffusion' or 'intermetallics'.