Al-Cu-Mg-Zn

The Al-Cu-Mg-Zn quaternary system is the basis of the 7000 series of wrought Al alloys. The formation of the major compounds such as Al2Cu, S_PHASE, T_PHASE, V_PHASE, and M (aka. η, modeled as C14_LAVES) is essentially determined by the quaternary phase equilibria. Small additions of other alloying elements such as Fe and Mn may form additional compounds, while the formation of those major compounds is barely affected. The 7000 series are heat treatable and a typical solution treatment is performed around 460 °C.

This example uses the TCS Al-based Alloy Database (TCAL).

Calculated isothermal sections of the Al-Cu-Mg-Zn system at 460 °C: at 8 wt. % Zn.

Figure 1: Calculated isothermal sections of the Al-Cu-Mg-Zn system at 460 °C: at 8 wt. % Zn [2012Che] with experimental data from [1948Str].

Calculated isothermal sections of the Al-Cu-Mg-Zn system at 90 wt.% Al.

Figure 2: Calculated isothermal sections of the Al-Cu-Mg-Zn system at 90 wt.% Al with experimental data from [1956Wri].

References

[1948Str] D. J. Strawbridge, A. Little, The Constitution of Aluminium Copper Magnesium Zinc Alloys At 460 °C. J. Inst. Met. 74, 191–225 (1948).

[1956Wri] E. H. Wright, Equilibrium relations at 460 °C in aluminum-copper-magnesium-zinc alloys of high purity (Internal Report 13–56-EC2, Aluminum Research Laboratories, Aluminum Company of America, 1956).

[2012Che] H.-L. Chen, Thermodynamic assessment of the Al-Cu-Mg-Zn(-Fe) and Al-Cu-Mg-Si multicomponent alloy systems (Stockholm, Sweden, 2012), unpublished work.