Optimierte AlMgMn-Legierungen für die Anwendungen im Automobilbau
Research output: Thesis › Doctoral Thesis
The importance of lightweight construction in the automotive industry rose significantly over the last years. Higher requirements regarding economic efficiency and fuel consumption as well as legal provisions pertaining the CO2 emission boost this development. An important step to reduce the car weight and therefore fulfil the legal restrictions of the CO2 emission is the substitution of steel car parts with parts made of aluminium. However, aluminium sheets, for example AlMgMn alloys, reach their maximum deformability when deformed into complex geometries. The present work deals with two challenges which arise while the production of outer car parts made of AlMgMn sheets. During deformation of AlMg and AlMgMn sheets at room temperature the deformation potential is limited because of the discontinuous dislocation movement at low strain rate sensitivities. These deformation conditions manifest in two phenomena, Lüders elongation and dynamic strain aging, which both lead to non-decorative sheet surfaces. By optimizing of the processing route, e.g. introducing pre-deformation, adjusting the cold rolling degree or different heat treatments, as well as an optimized chemical composition these optical manifestations shall be reduced or avoided. Additions of copper, zinc, zirconium and erbium, respectively, are evaluated. If AlMgMn sheets exhibit a very fine microstructure and special deformation conditions are applied, temperatures above 400 °C and deformation velocities under 10-2 s-1, they can deform superplastically. Maximum elongations of several hundred percent are possible. Based on an industrially produced AlMgMn alloy a higher deformation velocity and higher maximum elongation are targeted. Considering the active deformation mechanisms an optimized sheet variation shall be tested under application-oriented deformation conditions.
|Translated title of the contribution||Optimized AlMgMn Alloys for Automotive Applications|
|Publication status||Published - 2019|