This proposal examines three ternary aluminum alloys and one quartenary aluminum alloy system. Thermodynamic modeling and phase diagram calculations are coupled to solidification modeling to determine paths of solidification. Alloys of interest to the study are aluminum-rich alloys of Al-Mg-Cu, Al-Mg-Zn, Al-Zn-Cu, and Al- Mg-Zn-Cu. The approach combines thermodynamic modeling and experimental measurements of phase equilibria. A modified Schiel model is employed that accounts for back diffusion in determining the solidification path. Results from directional solidification experiments are compared with the calculations to improve the models. %%% A knowledge of the thermodynamics and phase equilibria of multi- component alloys is vital to the development of new alloys. This research expands basic understanding in this field for model aluminum alloys systems that also have commercial significance.
