Figure 14. Overview of input parameters, calculation steps, and results for the prediction of microstructures in aluminum alloys. Beside process parameters and casting geometry, alloy composition and metallurgical parameters, i.e. grain refinement, are defined at the beginning. This information is used by the program to calculate stable phases, which can be moved by the accelerated cooling the casting experiences (phase kinetics). The different solubility of alloying elements in the solid and liquid phase lead to segregation and potential creation of undesired phases. Finally, this information is used to calculate the solidification progress by calculating the temperature distribution in each time step. These steps are repeated at any location and at any time to locally predict microstructure and mechanical properties.


Figure 15. Differences between macroscopic and microscopic simulation (micromodeling) on simulated cooling curves. While the use of macroscopic heat transfer equations only modifies the shape of the cooling curve due to the released latent heat, micromodeling also considers the impact of different inoculation conditions (left). Even composition changes (i.e. change of effective Mg-content between 0.007% and 0.021%) modify the calculated undercooling, recalescense, and growth temperature (right).


14


International Journal of Metalcasting/Spring 10


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