Thermodynamic investigation of atomic order in AlMg liquid alloys

• Published in: Journal of physics. Condensed matter Vol. 3; no. 20; pp. 3635 - 3644
• Main Authors: Singh, N K P, Singh, R N, Choudhary, R B
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 20.05.1991; Institute of Physics
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Metals. Metallurgy; Physics; Solubility, segregation, and mixing; phase separation; Liquid state; Structure factor; Partition function; Thermodynamic model; Order parameter; Theoretical study; Short range order; Aluminium Magnesium Alloys; Free energy; Binary alloy
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/3/20/024

The grand partition function has been used to obtain analytic expressions for the excess free energy of mixing, the activity, the small-angle partial structure factors and the chemical short-range order parameter for weak interacting compound-forming molten alloys. It has also been applied to explain the asymmetry in the properties of mixing of AlMg molten alloys by assuming that the chemical complex Al sub 3 Mg sub 2 exists in the liquid phase. It is concluded that a reasonable degree of chemical order may exist in the concentration range 0.2 < = C sub Al < = 1.0, being greatest at 60 at.% of Al. In the magnesium-rich end (C sub Mg = > 0.8), however, the melt is close to the ideal mixture. The topological order, at least at the long-wavelength limit, has been found to depend only weakly on concentration. Phase diagrams, Graphs. 25 ref.--AA