EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

An important aspect of formability of Al sheet material in the automotive industry is the bendability without degradation of the surface quality. So far, microstructure, texture, the distribution of primary and secondary particles as well as these properties´ homogeneity over the sheet cross section are known as factors influencing the formability of Al-sheets. Recent studies for example evaluated bent EN-AW 6016 sheets and identified Copper and Brass as positive texture components which show a certain resistance against damage initiation via shear bands.
In the present study we include the analysis of microstructural features as primary- and secondary phases and the orientation- and position-dependent ability of the matrix to accommodate the external deformation. For this purpose, (partially interrupted) bending tests were performed on samples from the groups of 5xxx and 6xxx alloys after different processing parameters. Electron microscopic analyses including electron backscatter diffraction are utilized to identify the microstructural and texture changes during deformation. The analysis of deformation structure is comparatively straightforward, whereas the correct interpretation of a deformation-induced texture change is a more challenging aspect as the initial grain size is – especially in 6xxx alloys – large compared to the sheet thickness. Therefore, microstructure and texture can only together be correlated to the experimental bendability for identifying the most beneficial material properties.