Thermo-Fluiddynamical Investigation of the Melt Pool Area

• Applicant: Professor Dr.-Ing. Michael Schmidt
• Subject Area: Joining and Separation Technology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 434946896

As a flexible and contact-free joining technology, laser beam welding has increasingly gained importance. Processing of alloys with large melting range poses a challenge due to their solidification crack tendency. Solidification cracks form due to critical stress and strain states of the dendritic microstructure with interdendritic melt. Despite the high industrial relevance, current approaches are only addressing single aspects of the problem - either metallurgical- or structural-oriented ones. The research unit “Solidification Cracking during Laser Beam Welding – High Performance Computing for High Performance Processes” aims at developing quantitative process understanding of the mechanisms of solidification cracking and their relation to process parameters. The aim of the sub-project “Thermo-Fluiddynamical Investigation of the Melt Pool Area” is to understand the correlation between process parameters and properties relevant for solidification, such as the local temperature and the local chemical composition at the solidification front. Simulations will be used to analyze changes in alloying composition due to evaporation and the sensitivity of these changes depending on process parameter variation. Furthermore, the impact of local changes in chemical composition on local solidification temperatures will be examined. Relating to the solidification area, the influence of process parameters on shape and spatial characteristics of this so-called mushy zone will be investigated. If the mushy zone does influence these properties, the effect of varied process parameters on mushy zone formation will also be studied.Moreover, experiments will be used to examine if breaking or detaching dendrites appear, which act as condensation nuclei and thus influence the further progress of solidification. Both simulations and experiments will be used in this sub-project to answer the research questions. In close collaboration with the sub-project “Massively Parallel Simulation of the Melt Pool Area during Laser Beam Welding using the Lattice Boltzmann Method” an efficient, highly scalable and sustainable exascale simulation framework for the laser beam welding process will be developed to investigate the described questions. Modeling of the physics involved in the process necessary for setting up the exascale framework will take place within this sub-project. Implementation of the to-be-developed models will take place within the partnering project.

• DFG Programme: Research Units
• Subproject of: FOR 5134: Solidification Cracks during Laser Beam Welding: High Performance Computing for High Performance Processing
• International Connection: Russia, USA
• Cooperation Partners: Professor Craig Arnold, Ph.D.; Professor Dr.-Ing. Gleb Turichin, until 3/2022