MEASUREMENT OF THERMODYNAMIC PROPERTIES OF LIQUID Al-Mg ALLOYS
(P. O. Box317, School of Materials Science and Metallurgy,Norhteastern University, Shenyang110006, P. R. China)
Abstract: The activities of Mg element in liquid Al-Mg alloys were determined by electromotive force method in a cell made of BN crucible. The activities of Mg and Al as well as other thermodynamic properties were calculated from the measured EMF data. The results indicate that the Mg-concentration in the alloys at 1 073 K shows a negative deviation from Rault’s Law in the whole range of concentration. When XMg is≤0.55, the deviation is small; when XMg is >0.7, the deviation becomes large. When XMg is <0.126, the Mg concentration curve follows Henry’s Law, the Henry’s constant is 0.86. The behavior of Al is characterized by ideal solution in the range of 0≤XMg<0.8, which shows a positive deviation from Rault’s Law in the range of 0.58<XMg<0.8 and a negative deviation when XMg is >0.8.
Key words: Al-Mg alloys activity thermodynamic properties boron nitride