Cu Segregation around Metastable Phase in Al-Mg-Si Alloy with Cu

Abstract

Cu distribution around Q 0 -phase in an Al-1.0 mass% Mg 2 Si-0.5 mass% Cu alloy has been investigated by the analytical transmission electron microscope (TEM), energy-filtering TEM (EFTEM), and high angular annular dark field scanning TEM (HAADF-STEM) techniques in order to determine the effect of Cu on the precipitation of this alloy. Cu-segregation around rod-shaped precipitates in the sample aged at 523 K for 24 ks was confirmed by energy dispersive X-ray spectroscopy, elemental maps, and HAADF-STEM images. Cu-segregation was also detected from small precipitates, which show a hexagonal network with a lattice constant of 1.04 nm in their HRTEM images. Coarse rods show homogeneous distribution of Cu, and chemical composition is similar to that of coarse Q 0 -or Q-phase. Small precipitates less than 10 nm were also confirmed in as-quenched samples, and those precipitates seem to form during quenching.

Effects of Cryogenic Forging and Anodization on the Mechanical Properties and Corrosion Resistance of AA6066–T6 Aluminum Alloys

“…[20]. Cu atoms tend to segregate around the metastable phase in the Al-Mg-Si alloy, move to grain boundaries during the solution treatment, and diffuse to Mg-Si nanoparticles located at or near grain boundaries to finally form type-C precipitates [21] and the Q phase [22]. As a result, in this study, the T6 sample mainly contained the Q phase and Mg2Si precipitates after aging.…”

Al Flux Synthesis of the Oxidation-Resistant Quaternary Phase REFe4Al9Si6 (RE = Tb, Er)

“…One example of the importance of complex multinary compounds forming within Al alloys is Cu 2 Mg 8 Al 5 Si 6 , which has been shown to significantly increase matrix strength without increasing the overall weight. [19][20][21][22][23] Two elements commonly found in Al-based alloys are Fe and Si. [24][25][26][27] Iron is one of the most troublesome impurities.…”

TEM Observation of Cu and Ag Added Al-Mg-Si Alloy

“…This precipitation is similar to Q phase in the base-Cu alloy (Al-1.0%Mg 2 Si-0.2%Cu alloy in at.%) was .35Cu-0.35Ag, (b) 0.18Cu-0.18Ag. reported in Ref. [3]. On the other hand, precipitation observed in 0.35Cu-0.35Ag alloy aged at 523 K for 12 ks have 1120 direction of precipitate almost parallel to 100 Al of the matrix (Fig.…”