The EMF measurements in the Al-Mg system

Having several industrial applications the Al-Mg alloys were investigated i n solid state. The EMF technique with a liquid electrolyte was applied to o btain thermodynamic properties in one-phase and two-phase regions in centra l part of the system. Measurements were performed in two manners: 1 degrees for constant magnesium concentration X(Mg) = 0.410 and 0.475 and different temperatures, changing from T = 663 to 920 K, and 2 degrees for constant t emperature T = 673; 698 and 703 K, when the concentration of the alloy in t he cell was changed X(Mg) = 0.41 divided by 0.52 with the aid of the coulom etric titration. The EMF = f [T] or EMF = f [X (Mg)] relations was obtained in this way, as well as the points on the phase equilibrium lines of the s ystem. The determined results show that in the central part of the investigated sy stem, except beta and gamma solid phases, additionally only epsilon phase e xists for the concentration near X(Mg) = 0.44. There was not found existenc e of zeta phase. The epsilon phase appears as a result of the reaction beta + gamma = epsilon, at the temperature 698 or 700 K. That temperatures are about 16 K higher than that proposed in earlier papers.