Micromechanical modeling of fracture in high-pressure die cast aluminum

Sammanfattning

High-pressure die cast aluminum is being incorporated into the production of electricvehicles in order to increase vehicle efficiency and reduce manufacturing costs. Theprocess is known as Mega Casting and can produce large scale components with complexgeometry in one process, drastically reducing the amount of welds and joints.Due to the process, the aluminum components possess a complex microstructurewith different phases and porosity, which makes the mechanical properties difficultto predict. Today, there is a lack of Finite Element (FE) and material models thatcan capture these microstructural defects on a component scale.Throughout the project, a method for generation of three-phase microstructure modelsbased on Computer Tomography (CT) scanning and Scanning Electron Microscope(SEM) images is developed. Numerical studies on mesh design, time integrationand boundary conditions are performed with the intention to optimize computationalcosts while maintaining accuracy. Furthermore, the variation in mechanicalproperties depending on morphology is studied by simulating a range of differentmicrostructures subjected to different load cases.The results show that it is possible to generate three-phase microstructures thatrepresent the eutectic silicon region in HPDC-aluminum components. The choicesof the numerical model and modeling have impact on computational efficiency andaccuracy. Furthermore, it is possible to vary the internal morphology in the modelin order to obtain mechanical response data for a wide range of microstructures.