Abstract: The solidification paths of Al-Zn-Mg-Cu alloys and its precipitation behavior are analyzed using software package JMatPro 6.0 for material property simulation of Al-base alloys. The microstructures of the experimental alloys are analyzed; the experimental results of microstructural analysis are in agreement with the thermodynamic prediction. Through orthogonal experimental method, this paper designs the composition of Al-Zn-Mg-Cu alloys by studying the variation of η (MgZn2) phase, S (Al2CuMg) phase, T (AlZnMgCu) phase amount and precipitation temperatures with different Zn, Mg and Cu contents. It is found that with the optimum mass fraction of Zn of 6.7%, Mg of 2.2%—2.5% and Cu of 1.6%—2.0%, the mass fraction of η phase can be up to 8.7%—9.22% and that of S phase and T phase can be lower than 0.5%.

Key words: Al-Zn-Mg-Cu alloys|thermodynamic calculation|composition design

摘要： The solidification paths of Al-Zn-Mg-Cu alloys and its precipitation behavior are analyzed using software package JMatPro 6.0 for material property simulation of Al-base alloys. The microstructures of the experimental alloys are analyzed; the experimental results of microstructural analysis are in agreement with the thermodynamic prediction. Through orthogonal experimental method, this paper designs the composition of Al-Zn-Mg-Cu alloys by studying the variation of η (MgZn2) phase, S (Al2CuMg) phase, T (AlZnMgCu) phase amount and precipitation temperatures with different Zn, Mg and Cu contents. It is found that with the optimum mass fraction of Zn of 6.7%, Mg of 2.2%—2.5% and Cu of 1.6%—2.0%, the mass fraction of η phase can be up to 8.7%—9.22% and that of S phase and T phase can be lower than 0.5%.

关键词: Al-Zn-Mg-Cu alloys|thermodynamic calculation|composition design