Hybrid interaction during and after thixoforging of multi material systems

• Applicant: Professor Dr.-Ing. Mathias Liewald
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2016 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 313885700

In times of rising energy and resource costs, improvement of efficiency in production and application is an important technological driver for development and optimization of manufacturing processes. Thereby, an effective input for saving energy and the conservation of resources is contributed by weight reductions within the production of locally optimized and on load cases adapted hybrid components.The aim of this research project is to develop the process for thixoforging of hybrid components with metal-to-metal bonds. Thereby, the characterization of the intermetallic phases occurring both during and after the thixoforging process between the different metallic materials is a major research topic. In the first funding period, the focus was on the development of two process routes as well as the specific design of the metallic compounds to be produced, taking into account the interaction mechanisms occurring in the joining and transition zones of the different materials. While in the first funding period, simple disk components were initially produced in the course of the real forming tests, a non-rotationally symmetrical component geometry with more complex flow paths is to be implemented in the second funding period in order to gain a deeper understanding of the flow behaviour during simultaneous forming of two different semi-liquid metal alloys. Furthermore, the deficits that occured in the simulative illustration of thixoforging of hybrid semi-finished products during the first funding period are to be remedied by the proposed research work in the second funding period.The following scientific objectives will be pursued within the second funding period:- Investigations of the joint forming of graded semi-finished products by thixoforging taking into account complex flow paths and modelling of the material flow by means of FEM simulation- Development of a numerical model for FEM simulation in order to describe thixotropic material properties by flow curves of different semi-solid metal alloys- Investigations of the material transitions between the different materials during heating and after the forming process- Determination of the functional properties of the hybrid components and in particular the mechanical properties of the crated joining zones- Transfer of the knowledge gained to hybrid semi-finished products made of materials with significantly diverging melting points (temperature difference > 100 K)

• DFG Programme: Research Grants