Effects of the Mg/Si Ratio on Microstructure, Mechanical Properties, and Precipitation Behavior of Al–Mg–Si–1.0 wt %-Zn Alloys

Abstract

Aluminum alloys are widely used as first-choice materials for lightweight automotive applications. It is important that an alloy have a balance between strength and formability. In this study, the alloys were melted, cast, hot rolled, and cold rolled into 1 mm-thick sheets. The microstructure, mechanical properties, and precipitation behavior of Al–Mg–Si–1.0 wt %-Zn alloys with Mg/Si ratios of 0.5, 1, and 2 after solution treatment were studied using optical and electron microscopy, a tensile test, the Vickers hardness test, and differential scanning calorimetry. The results showed that a high density and number of Al–Fe–Si particles were observed in the matrix, thus causing the formation of more homogeneous and smaller recrystallized grains after treatment with the solution. In addition, a higher volume fraction of cubeND and P-types texture components formed during solution treatment. Also, a high r value and excellent deep drawability were achieved in the medium-Mg/Si-ratio alloy. The formation of denser strengthening precipitates led to a better paint-bake hardening effect in comparison with the other two alloys. Furthermore, the precipitation kinetics were enhanced by the addition of Si, and the addition of Zn did not alter the precipitation sequence of the Al–Mg–Si alloy. The dual-phase strengthening effect was not achieved in the studied alloys during paint-bake treatment at 175 °C.

Influence of Zn and Sn on the Precipitation Behavior of New Al–Mg–Si Alloys

“…Zinc does not form clusters by itself, but stimulates the nucleation and growth of Mg–Si co-clusters. These findings agree well with those in the literature [17,30,31,32]. Zn has an attractive vacancy binding energy [33,34]) and it can thus be assumed that when Zn atoms are present, more vacancies survive the quenching procedure.…”

Solidification and Precipitation Microstructure Simulation of a Hypereutectic Al–Mn–Fe–Si Alloy in Semi-Quantitative Phase-Field Modeling with Experimental Aid

“…The limited solubility of Fe in the solid α-Al phase induced severe segregation of Fe in the interdendritic liquid channel, which led to the formation of Fe-concentrated precipitate in the last stage of solidification. To resolve the difference between the primary and interdendritic precipitates, a 3D simulation was conducted with a domain size of 125 × 125 × 125 μm 3 . An α-Al nucleus was placed in the corner of the domain, and the symmetric boundary conditions for the x, y, and z directions were applied based on the cubic symmetry of the face-centered cubic α-Al phase.…”

“…Precipitation behavior in Al alloys is of great interest due to its strong influence on the mechanical properties through a hardening effect [1][2][3]. Small changes in the concentrations of alloying elements or heat treatment conditions can readily alter the mechanical properties and product quality by modifying the microstructure.…”

Effect of Laminar Flow on the Corrosion Activity of AA6061-T6 in Seawater

“…According to EDS (Table 2), zone A is characterised by its higher content of Al, O, and Cl, which could relate to corrosion products. According to previous studies, at pH > 8.5, Al(H2O)6 3+ cations appear, while in the range of pH 4.5-8.5, Al(OH)3 predominates [37,38]. In chloride solutions, aluminum metal ionises rapidly to the Al 3+ ion, which also hydrolyzes very rapidly (owing to the negative potential value) [39].…”

“…3+ cations appear, while in the range of pH 4.5-8.5, Al(OH) 3 predominates [37,38]. In chloride solutions, aluminum metal ionises rapidly to the Al 3+ ion, which also hydrolyzes very rapidly (owing to the negative potential value) [39].…”