Correlation of textures and hemming performance of an AA6XXX aluminium alloy

Abstract The hemming process is one of the most commonly used forming processes for aluminium alloys in the automotive industry and requires bending the aluminium alloy sheet to 180° without generating cracks or surface cosmetic defects. However, existing commercial Al–Mg–Si alloys (AA6xxx aluminium alloys) used in the automotive industry could easily fail during the hemming process. Textures in sheet aluminium alloys are commonly known as influential in the deformation behaviour and surface defect formation, while a comprehensive correlation of textures and hemming performance of aluminium alloy sheets is not well established. In this work, the influence of different texture components on the hemming behaviour of an AA6XXX aluminium alloy sheet was thoroughly investigated. The hemming testing was carried out using samples taken along rolling and transverse directions and a quantitative approach via profilometer was used to measure the hemming performance. The detailed grain orientation spread analysis, Taylor factor and Schmid factor analysis with different texture components from EBSD characterizations show that the dominance of Cube and CubeND texture component contributes to the hemming performance. CubeRD and Goss texture components could only benefit the hemming performance at one of the bending directions. In contrast, Brass and Goss texture components in Bent_RD and P component in Bent_TD may not be preferred for the hemming performance.