Modelling of the Precipitated Phases and Properties of Al-Zn-Mg-Cu Alloys

Abstract

The effects of Zn and Mg variations on the precipitated phases and the properties of Al-Zn-MgCu alloys are investigated in this study. The quantities of stable and metastable phases have been calculated under various Zn and Mg contents by using software package JmatPro. The results show that the amount of the main hardening g (MgZn 2 ) phase and g¢ phase increase with higher Zn and Mg contents. T (AlCuMgZn) phase and metastable counterpart significantly increase with the reduction of Zn contents or the increase of Mg contents. S (Al 2 CuMg) phase reduces gradually with the increase of Mg content, while S phase varies only slightly with the Zn content. The precipitation of GP zones is promoted by the increase of Zn or Mg content. The physical and mechanical properties of the alloys have been modelled in such way that increasing Zn or Mg content could reduce electrical conductivity and thermal conductivity, while the mechanical properties improve with increasing Zn content and varies markedly as Mg content changes from 2.7 to 2.9 wt.%.

Effect of Alloying Element on the Integrity and Functionality of Aluminium-Based Alloy

“…For Mg variation, the strength property of the alloy improves in the range of 2.7-2.9 wt.% Mg, Increase of Mg contents will reduce the electrical conductivity and thermal conductivity. In general, the experimental evidence for microstructures is in accordance with the predictions in the modeling processes [21]. …”

Microstructure and texture characterization of 7075 Al alloy during the SIMA process

“…These are common precipitates in Al-Zn-Mg-Cu alloys which are also observed in the microstructure of wrought 7075 sample (Fig. 3), and were similar to those reported by other researchers (Mahathaninwong et al, 2012;Xinyu et al, 2011;Yu and Li, 2011). Dimensions of these precipitates are commonly greater than 1 μm, and therefore during deformation a special zone develops in the vicinity of such non-deformable particles, which is characterized by a high local strain and high misorientation gradient.…”

Effect of temperature and pressure on mechanical, surface and electrochemical properties of Al-1.5Cu-5.5Zn-2.5Mg (Alumix-431)

“…S(Al 2 CuMg) phase on the low Cu content where Cu/Mg ratio is close to one (Wu et al, 2014). The S(Al 2 CuMg) phase in the microstructure is occurred because of high Cu1Mg content ($4.0 per cent) of this alloy (Mondal and Mukhopadhyay, 2005;Wu et al, 2014;Yu and Li, 2011). S phase reduces corrosion resistance and increases mechanical properties (Lin et al, 2014).…”