Verbesserung des Umformverhaltens von mehrlagigen Aluminiumblechwerkstoffen mit ultrafeinkörnigem Gefüge

Description

Multilayered aluminum sheet metal that is produced using the Accumulative Roll Bonding (ARB) process shows nanocrystalline grain structure and enhanced mechanical strength. Despite limited formability, in combination with process- and application-adapted property gradients these materials offer the potential to achieve weight reduction regarding the car body. For the exploitation of that potential, within the framework of this work at first the upscaling of the ARB process is analyzed starting from the laboratory scale to enable the production of large-scaled blanks. Subsequently, specific property gradients are realized over the sheet plane and in thickness direction applying local heat treatment processes. These should lead to an enhancement of the formability due to local softening on the one hand and the local increase of the bond strength of the layers on the other hand. Therefore, the particular effects on the forming behavior are analyzed and evaluated in deep drawing and bending tests. Finally, the mechanisms for Tailor Heat Treated Blanks (THTB) are extended according to the findings of this work and guidelines for the design of tailored and locally heat treated blanks out of multilayered aluminum are defined.