PHASE DIAGRAMS AND THEIR APPLICATIONS TO Mg ALLOYS

Abstract

This work summarizes the basics of phase diagrams and their relation to the Calphad method. It is emphasized that the benefits of quantitative prediction of phase formation of selected multicomponent alloys under equilibrium and special off-equilibrium processing conditions require the development of reliable and consistent thermodynamic descriptions forming a Calphad-type thermodynamic database. The implications of intermetallic phases in multicomponent Mg alloys are explained for ternary Mg-Ce-La/Nd alloys. An introduction to applications of this approach to phase formation in as-cast and heat treated Mg alloys is given and discussed in detail for the example of ternary Mg-Al-Zn alloys. The extension to truly multicomponent alloy systems and advanced kinetic calculations is briefly depicted.