Thermodynamic Analysis of the Al-Mg-Zn Ternary System
- 1 May 2020
- journal article
- research article
- Published by Japan Institute of Metals in Journal of the Japan Institute of Metals and Materials
- Vol. 84 (5), 141-150
- https://doi.org/10.2320/jinstmet.jbw201905
Abstract
In the present study, the Al-Mg-Zn ternary system, which is essential as the basic system of 7000 Al-based alloys and Mg-based casting alloys, was analyzed thermodynamically using the first-principles method and the CALPHAD approach. The (Al,Zn)17Mg21-type sublattice model was applied to the ternary compound ɸ phase based on the most recent experimental results. Furthermore, the Gibbs free energy for Al17Mg21 and Zn17Mg21 which are end members of the structures, the terminal compounds Al2Mg and Zn2Mg of Laves_C14 phase, as well as Mg2Zn11 phase were evaluated by first-principles calculations considering lattice vibration and volume expansion. These results were analyzed by the CALPHAD method together with experimental values on phase boundaries and thermodynamic properties, and the phase equilibrium of all compositional regions of this alloy system was clarified by calculations. The temperature change of the precipitation phase based on the analysis was found that the AlMg-γ phase mainly formed at the high temperature in the commercial AZ alloys. On the other hand, when the ratio of Zn:Al was changed, the precipitated phase altered to the τ phase or the ɸ phase, and therefore, it can be inferred that the mechanical properties in this alloy system may be expected to be improved by the structure change due to the composition change.Keywords
This publication has 25 references indexed in Scilit:
- The α-Mg solvus and isothermal section of Mg-rich corner in the Mg–Zn–Al ternary system at 320°CJournal of Alloys and Compounds, 2009
- The crystal structure of the equilibrium Φ phase in Mg–Zn–Al casting alloysActa Materialia, 2001
- Heat Resistance of Mg-Zn-Al-Ca Alloy CastingsMaterials Science Forum, 2000
- TEM study of continuous precipitation in Mg–9 wt%Al–1 wt%Zn alloyActa Materialia, 2000
- An investigation of the properties of Mg-Zn-Al alloysScripta Materialia, 1998
- Experimental investigation and thermodynamic calculation of the Al–Mg–Zn systemThermochimica Acta, 1998
- A review and thermodynamic assessment of the Al-Mg and Mg-Li systemsCalphad, 1990
- Über die Ternären Legierungen von Magnesium, Zink und CadmiumZeitschrift für anorganische und allgemeine Chemie, 1912
- Über die ternären Legierungen von Magnesium, Zink und Cadmium. I. MitteilungZeitschrift für anorganische und allgemeine Chemie, 1910
- Metallographische Mitteilungen aus dem Institut für anorganische Chemie der Universität Göttingen. XXV. Über die Legierungen des Magnesiums mit Kadmium, Zink, Wismut und AntimonZeitschrift für anorganische und allgemeine Chemie, 1906