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JPEDAV (2007) 28:218–220 DOI: 10.1007/s11669-007-9035-8 1547-7037 ÓASM International

Al-Cu-Fe-Mg-Si (Aluminum-CopperIron-Magnesium-Silicon) V. Raghavan

One of the early reports on this quinary system is by [1950Phr]. [2002Bel1, 2002Bel2] studied the phase equilibria in Al-rich alloys with a constant Cu content of 10 mass% and up to a few percent each of Fe, Mg and Si. They constructed plots to show the solidification reactions, the phase distribution in the solid state and the polythermal section at 10Cu-1.5Mg-0.5Si (in mass%). Earlier, [1998Bel] reported similar results in Al-rich alloys with a constant Si content of 10 mass%.

Quinary Phase Equilibria

Updates on the Al-Cu-Fe-Si, Al-Cu-Mg-Si and Al-FeMg-Si systems appear in this issue. In the Al-Cu-Fe-Mg system, [2002Bel1] found no quaternary phases in Al-rich alloys. [1950Phr] investigated all the above four quaternary systems, as a first step to the study of this quinary system. The ternary and quaternary phases found in the alloy compositions investigated by [2002Bel1] and [1998Bel] are denoted as follows: Al2CuMg (denoted S), Al7CuFe (denoted N by [2002Bel1]), FeSiAl5 (b), Cu2Mg8Si6Al5 (Q) and Fe2Mg7Si10Al18 (p).

With starting metals of 99.99% Al, 99.9% Cu, 99.95% Mg, 99.99% Si and an Al-Fe master alloy, [1998Bel] melted and cast in air Al-rich alloys containing a constant Si content of 10 mass%, and smaller quantities of Cu, Fe and Mg. The phase equilibria were studied with scanning electron microscope and electron probe microanalysis. The temperatures of the phase changes were determined by thermal analysis. Assuming that (Al) solidified first and then (Si), followed by other ternary and quaternary solidification reactions, [1998Bel] projected the liquidus on a triangle as shown in Fig. 1. All regions contain additionally (Al) and (Si). The liquidus lines correspond to five-phase equilibrium. For example, p2-U2 and e1-E lines refer to the equilibrium L + FeSiAl5 M (Al) + (Si) + p and L M (Al) + (Si) + Q + h, respectively. The final solidification is through the six-phase eutectic reaction (point E): L M (Al) + (Si) + Q + h + p. Using the observation that all their alloys necessarily contain (Al) and (Si), [1998Bel] plotted the phase distribution in the solid state on a triangle, Fig. 2. All phase regions contain additionally (Al) and (Si). A polythermal section at constant 5Cu-0.4Mg-10Si (in mass%) is shown in Fig. 3. [1998Bel] also derived isothermal sections

Fig. 1 Al-Cu-Fe-Mg-Si liquidus in Al-rich alloys with 10 mass% Si, projected from Al apex. All regions have additionally (Al) and (Si) [1998Bel]

Fig. 2 Al-Cu-Fe-Mg-Si phase distribution in the solid state in Al-rich alloys with 10 mass% Si. All regions have additionally (Al) and (Si) [1998Bel]

Quaternary Systems

218

Journal of Phase Equilibria and Diffusion Vol. 28 No. 2 2007

Section II: Phase Diagram Evaluations

Fig. 5 Al-Cu-Fe-Mg-Si polythermal section at 10Cu-0Fe-2Mg (in mass%) [2002Bel1]

Fig. 3 Al-Cu-Fe-Mg-Si polythermal section at 5Cu-0.4Mg-10Si (in mass%) [1998Bel]

Fig. 4 Al-Cu-Fe-Mg-Si pol