Diffusivities in liquid and fcc Al-Mg-Si alloys and their application to the simulation of solidification and dissolution processes

The experimental viscosities and diffusivities in Al-Mg-Si melts as well as the experimental diffusivities in fcc Al-Mg-Si alloys available in the literature were first critically reviewed. The Sutherland equation was then employed to convert the experimental viscosity data into self-/tracer diffusivity data in Al-Mg-Si melts. Based on the experimental diffusivities together with the converted ones, the atomic mobilities in liquid and fcc phases of the Al-Mg-Si system were assessed by means of DIffusion-Controlled TRAnsformation (DICTRA) software package. Comprehensive comparisons showed that most of the measured and converted diffusivities in liquid and fcc Al-Mg-Si system can be reasonably reproduced by the currently obtained atomic mobilities. Moreover, the reliability of the established atomic mobilities of liquid and solid phases were further verified by two typical cases in Al-Mg-Si alloys during solidification and dissolution processes. The simulation results agree well with the experimental information, not only validating the reliability of the atomic mobilities, but also demonstrating the importance of the accurate atomic mobility database in quantitative simulation of microstructure during various preparation processes.