Re-investigation of phase equilibria in the system Al–Cu and structural analysis of the high-temperature phase η1-Al1−δCu
| Autor: | Christian L. Lengauer, Klaus W. Richter, Norbert Ponweiser |
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| Jazyk: | angličtina |
| Předmět: |
Diffraction
Materials science Chemistry(all) Scanning electron microscope Mechanical Engineering B: Crystal chemistry of intermetallics Metals and Alloys Thermodynamics General Chemistry Article law.invention Crystallography Optical microscope law Mechanics of Materials Lattice (order) Differential thermal analysis A: Aluminides Miscellaneous Materials Chemistry Orthorhombic crystal system Thermal stability B: Crystallography Phase diagram B: Phase diagrams |
| Zdroj: | Intermetallics |
| ISSN: | 0966-9795 |
| DOI: | 10.1016/j.intermet.2011.07.007 |
| Popis: | 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. Graphical abstract Highlights ► Complete reinvestigation of the Al–Cu phase diagram. ► Several new phase equilibria established. ► Structure of η1 solved by high temperature XRD. |
| Databáze: | OpenAIRE |
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