The solidification of magnesium-rich alloys containing Al, Ca, and Sr

The thermodynamic description of the Mg-Al-Ca-Sr quaternary system in the magnesium-rich region was developed on the basis of the authors' previous work on the key constituent ternaries, such as Mg-Al-Ca and Mg-Al-Sr systems. Using this description coupled with the Scheil model, the calculated solidification paths of several Mg-Al-Sr ternary alloys and Mg-Al-Ca-Sr quaternary alloys are in good accordance with experimental results from directional solidification as well as published results from cast alloys. These results validate the reliability of the present thermodynamic description of the Mg-Al-Ca-Sr quaternary system in the magnesium-rich region. More importantly, the predicative nature of the calculation either using only thermodynamic data or coupled with the kinetic model makes it possible to exploit new alloy compositions where experimental investigation has not been attempted.