Influence of Microstructure on the Folding Behavior of Crash Relevant Aluminum Extrusion Parts

Aluminum, especially extrusions of the 6xxx series, has considerable potential to make cars lighter and thus more economical. Over time, requirements have been changed to higher strength for profiles with lower wall thickness including, in particular, better energy absorbing behavior. Crash relevant aluminum parts in aluminum spaceframe constructions should have high mechanical properties combined with highest energy absorption capability. Such parts absorb energy by controlled folding.Until now, the factors of influence on the folding behavior are not completely clarified. Possible factors are microstructure parameters such as grain size, grain structure and phase structure. Therefore the TRIMET Aluminium SE investigated the correlation between the folding behavior and various microstructure parameters. This paper describes material, the heat treatment experiments for varying the microstructure und the correlations between the folding behavior and the microstructure. Finally conclusions and recommendations for optimizing the folding behavior are described.