Project Details
Projekt
Reduction of plastic anisotropy and improved formability of novel magnesium alloy sheets through utilization of Equal-Channel Angular Pressing (ECAP)
Subject Area
Primary Shaping and Reshaping Technology, Additive Manufacturing
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 455383045
The main objective of this project is to understand the physical mechanisms involved during warm forming and provide guidelines to significantly reduce the anisotropy while maintaining the good formability of magnesium Mg-Zn-RE and Mg-Zn-Ca alloy sheets. Both alloy systems are known by the good stretch formability even at room temperature. The analysis and improvement of mechanical and forming behavior of both alloy systems are scientific and application oriented relevant. With special emphasis in the Mg-Zn-Ca system, which does not use the strategic RE elements, applications in the automotive industry and biomedical sector are feasible within the near future. However due to the distinctive texture development after conventional rolling and annealing, they show strong anisotropic deformation and forming behavior, i.e. significantly difference in the work hardening rate (WHR) along different directions with respect to RD and development of strong earing after deep drawing. In this regard, this project deals with the processing of Mg sheets by means of severe plastic deformation to use the potential of texture engineering via shear strain. Preliminary works already showed that with Equal-Channel Angular Pressing (ECAP) for sheet metal, it is feasible to enhance the mechanical behavior of Mg-Zn-RE alloy. The utilization of this unique process can serve to systematically tailor the crystallographic texture of the workpiece to investigate its effect on the forming behavior at temperatures below 200 °C. In addition to this, coupled finite element (FEM) and crystal plasticity (CP) simulations are proposed not only to provide a sound understanding on ways to tailor the crystallographic texture during ECAP processing, but also give insights in the effect of the activation of slip and twinning modes during forming tests. It is important to highlight that both alloy systems are known by limited dynamic recrystallization during forming at temperatures below 200 °C, which will allow a rather good prediction of the simulated plastic activity of deformation mechanisms. The validation of the mechanical and forming properties will then be carried out at different temperatures and strain rates close to practical application. Such a detailed validation will prove the functionality of these basic investigations and will provide guide lines to reduce the anisotropy of these formable alloys. At the end of the funding period, a state of knowledge is to be developed that will allow the production of an high formable and texture reduced magnesium sheet using tailor-made sub-processes, thus opening up the use of magnesium for other sub-sectors and achieving further progress in the field of lightweight construction.
DFG Programme
Research Grants
Co-Investigators
Dr.-Ing. Roland Golle; Dr. Dietmar Letzig
