Graser Matthias

Dr. Matthias Graser



  • Improvement of formability of extruded aluminium profiles by a local short-term heat treatment

    (Third Party Funds Single)
    Aim of the research project is the enhancement of the forming limit and the adjustment of the final mechanical properties of curved aluminum profiles by tailored heat treatment before the forming process. The influence of a short term heat treatment on aluminium profiles and the interaction with subsequent bending operation will be investigated fundamentally. This is a significant enhancement of the state of the art. Until now, in particular, fast hardenable aluminum blank alloys, which were especially developed for a short term heat treatment, were analyzed. The influence of a short term heat treatment on the mechanical properties of extruded aluminum profiles is not investigated yet. Regarding the influence on the microstructure there is only basic knowledge. On the one hand it is to be analyzed what microstructure and property changes can be induced due to the thermal treatment and how they can be controlled by a heat treatment process. Based on the basic understanding an appropriate property distribution should be determined in order to extend the forming limit, taking into account the complex stress and strain state in profile bending. Criteria for the improvement will be the contour accuracy achieved during the forming process or the reduction of the bending radius for the same cross-sectional deformation. The heat treatment will be designed using a thermo-mechanically coupled simulation which can determine the change of the mechanical properties derived by microstructural dissolution of precipitations. Finally, the question arises, how the interaction of a heat treatment and a bending operations affect the subsequent aging mechanisms and which final properties at the end of the process chain can be realized.