Solidification and Microstructure of Mg - Al - (Ca, Sr, Ce, La) Ternary Alloys

摘要

Solidification behavior and as-cast microstructure have been analyzed in a series of ternary Mg alloys consisting of Mg - Al -X: (Ca, Sr, Ce, La). Thermodynamic calculations of the Mg - Al - Ca , Mg - Al -Sr, and Mg - Al - Ce ternaries were conducted to predict the solidification path of the Mg - 4 Al - 4 X and Mg - 4 Al - 2 X systems. Thermal analyses of the solidification process and accompanying electron microscopy studies of as-cast microstructure were conducted on the same alloys. Scheil calculations and the experimental measurements of liquidus and solidus temperatures are compared. All microstructures consisted of primary α-Mg grains with intermetallic phases along the grain boundaries. Additions of Ca and Sr widen the solidus to liquidus gap to a much greater degree than equivalent levels of Ce and La.