Igor Chumak

Experimental investigation and thermodynamic calculation of ternary Al–Ca–Mg phase equilibria

The ternary Al-Ca-Mg phase equlibria were investigated using X-ray diffraction methods, metallography, scanning electron microscopy with energy- and wave-length-dispersive X-ray microanalysis, and differential thermal analysis. The phase diagram was determined in the complete composition range. Large ternary solubilities were found for the binary phases CaMg 2 , Al 2 Ca and Al 3 Ca 8 . Microstructures of samples with compositions near the ternary monovariant eutectic L → CaMg 2 + Al 2 Ca show remarkable rod-like crystals that are identified as intergrowth between CaMg 2 and Al 2 Ca. A consistent thermodynamic model was developed using the Calphad method incorporating all experimental data. It was used to calculate all pertinent phase equilibria of the Al-Ca-Mg system.