The phase equilibria and reaction temperatures in the system Al–Cu were re-investigated by a combination of optical microscopy, powder X-ray diffraction (XRD) at ambient and elevated temperature, differential thermal analysis (DTA) and scanning electron microscopy (SEM). A full description of the phase diagram is given. The phase equilibria and invariant reactions in the Cu-poor part of the phase diagram could be confirmed. The Cu-rich part shows some differences in phase equilibria and invariant reactions compared to the known phase diagram. A two phase field was found between the high temperature phase η1 and the low temperature phase η2 thus indicating a first order transition. In the ζ1/ζ2 region of the phase diagram recent findings on the thermal stability could be widely confirmed. Contrary to previous results, the two phase field between δ and γ1 is very narrow. The results of the current work indicate the absence of the high temperature β0 phase as well as the absence of a two phase field between γ1 and γ0 suggesting a higher order transition between γ1 and γ0. The structure of γ0 (I-43m, Cu5Zn8-type) was confirmed by means of high-temperature XRD. Powder XRD was also used to determine the structure of the high temperature phase η1-Al1−δCu. The phase is orthorhombic (space group Cmmm) and the lattice parameters are a = 4.1450(1) Å, b = 12.3004(4) Å and c = 8.720(1) Å; atomic coordinates are given.

中文翻译：

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Al-Cu体系相平衡的再研究和高温相η1-Al1-δCu的结构分析

通过光学显微镜、室温和高温下的粉末 X 射线衍射 (XRD)、差热分析 (DTA) 和扫描电子显微镜 (SEM) 的组合重新研究 Al-Cu 系统中的相平衡和反应温度. 给出了相图的完整描述。可以确认相图中贫铜部分的相平衡和不变反应。与已知相图相比，富铜部分显示出相平衡和不变反应的一些差异。在高温相 η1 和低温相 η2 之间发现了两相场，因此表明发生了一级转变。在相图的 ζ1/ζ2 区域，最近关于热稳定性的发现可以得到广泛证实。与之前的结果相反，δ 和 γ1 之间的两相场非常窄。当前工作的结果表明不存在高温 β0 相以及 γ1 和 γ0 之间不存在两相场，这表明 γ1 和 γ0 之间存在高阶跃迁。γ0（I-43m，Cu5Zn8型）的结构通过高温XRD证实。粉末 XRD 还用于确定高温相 η1-Al1-δCu 的结构。相为正交相（空间群 Cmmm），晶格参数为 a = 4.1450(1) Å，b = 12.3004(4) Å 和 c = 8.720(1) Å；给出了原子坐标。Cu5Zn8 型）通过高温 XRD 证实。粉末 XRD 还用于确定高温相 η1-Al1-δCu 的结构。相为正交相（空间群 Cmmm），晶格参数为 a = 4.1450(1) Å，b = 12.3004(4) Å 和 c = 8.720(1) Å；给出了原子坐标。Cu5Zn8 型）通过高温 XRD 证实。粉末 XRD 还用于确定高温相 η1-Al1-δCu 的结构。相为正交相（空间群 Cmmm），晶格参数为 a = 4.1450(1) Å，b = 12.3004(4) Å 和 c = 8.720(1) Å；给出了原子坐标。