Experimental Study of the Ternary Phase Diagram Al–Ge–Mg

Abstract

The phase equilibria of the Al-Ge-Mg ternary phase diagram were experimentally studied at the temperatures of 250, 300, 400 and 450 °C. The ternary phase τ (Al2Ge2Mg) suggested by the earlier structural study was found to be stable at all temperatures studied. Detailed study of the phase equilibria containing the τ (Al2Ge2Mg) phase in the ternary system have been carried out. The average composition of this phase was found to be 36 at.% Al-36 at.% Ge–Mg. In contrast to the previously published binary Ge–Mg phase diagram, the solubility of Mg in Ge was found to be within a few atomic percent. It was also found that GeMg2 intermetallic phase dissolves only small amount of Al but there is significant nonstoichiometricity with respect to the Ge/Mg ratio especially for lower annealing temperatures.