The aluminium-copper system

Abstract

A critical assessment is given of the phase equilibria of the AI-Cu system. In the first section, the stable equilibrium diagram is constructed. In the second section, metastable and constrained equilibria are considered. These include metastable solvus curves of the AI-rich side of the diagram; on the Cu-rich side, transformations involving the metastable bcc phase include the order-disorder transition, metastable invariant reactions, and martensitic and massive transformation. In the third section, crystal structure and lattice-parameter data are reviewed. Finally, new calculations of selected phase equilibria are presented which are based on computer optimization of phase-diagram and thermochemical data. IMR/14;2

Phase diagram of Au-Al-Cu at 500 °C

“…6, covering most of the binary and ternary phases. All of the binary intermediate phases in Al-Au [6] and Al-Cu [7] were identified in this study. For the Au-Cu [8] system, only the α (Au, Cu) phase appeared at 500°C.…”

“…Al-Au binary systems exhibit five intermediate phases at 500°C, namely, AuAl 2 , AuAl, Au 2 Al, Au 8 Al 3 (Au 5 Al 2 ), and Au 4 Al [6]. Al-Cu binary systems exhibit five intermediate phases at 500°C, namely, θ (Al 2 Cu), η 2 (AlCu), ζ 2 (Al 9 Cu 11 ), δ (Al 2 Cu 3 ), and γ 1 phases [7]. Au-Cu binary systems form solid solution at 500°C [8].…”

Influence of the Al content on the phase transformations in Cu-Al-Ag alloys

“…In curves (a) and (b) five endothermic peaks were observed, while in curve (c) only three peaks were detected. Peak P1, at about 559 ºC, is due to the α + γ 1 ↔ β eutectoid transformation [10], as expected from the Cu-Al equilibrium diagram [9]. The endothermic peak P 2 , at about 508 ºC, is associated to the β 1 phase disordering.…”

“…Figure 4 shows the DTA curves obtained at a heating rate of 20 ºCmin -1 for the Cu-9wt.%Al-4wt.%Ag (curve a), Cu-10wt.%Al-4wt.%Ag (curve b) and Cu-11wt.%Al-4wt.%Ag (curve c) alloys fig. 4 the endothermic peak P 1 , at about 559 ºC, is due to the α + γ 1 ↔ β eutectoid transformation [10] and the endothermic peak P 2 , at about 525 ºC, is attributed to the β 1 → β transition from the remaining part of the β 1 phase formed at low temperature [8]. The endothermic peak P 3 , at about 480 ºC, is associated to the reverse martensitic transformation and to the β 1 → α + γ 1 decomposition from part of the β 1 phase.…”

An Inert Metal Anode for Magnesium Electrowinning

“…These alloys share a number of desirable characteristics for this application, including: The compositions selected are Cu with 17 at.% and 23 at.% Al, which at the cell operating temperature (720°C) represent the a (fee) and B (bee) solid solution phases, respectively. [9] Although the ct phase alloy is stable to room temperature, the @phase is known to separate below 567°C into a mixed ct and y phase. The addition of certain ternary components at concentrations as low as 0.5 at.% is sufficient to stabilize the~phase to room temperature, which has important implications for anodes that are heat treated prior to use.…”