Regensburg 2002 – wissenschaftliches Programm
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M: Metallphysik
M 10: Quasikristalle III
M 10.4: Fachvortrag
Dienstag, 12. März 2002, 15:15–15:30, H6
Formation conditions of quasicrystals in ternary alloys of Al-Co with Cu, Ni, Pd and Ag — •Mariya Yurechko1,2, Benjamin Grushko1, Shaobo Mi1, and Tamara Velikanova2 — 1Institut fuer Festkoerperforschung, Forschungszentrum Juelich, D-52425 Juelich, Germany — 2I.N. Frantsevich Institute for Materials Science, National Academy of Science of Ukraine, 03680 Kiev 142, Ukraine
Formation of icosahedral and decagonal quasicrystals was observed in binary systems of aluminum with transition metals from V to Ni, from Mo to Pd, from W to Ir [1]. These structures were only observed in metastable states. With addition of Cu and Ni several ternary systems based on the above mentioned binary Al-TM systems exhibited thermodynamically stable quasicrystals. In particular they are Al-Cu-Co and Al-Ni-Co containing the stable D-phase which is the ternary extension of the metastable Al-Co D-phase [2]. While the Al-Cu-Co and Al-Ni-Co phase diagrams were extensively studied, the Al-Co-Pd and Al-Co-Ag phase diagrams were not yet studied. Ni and Cu as well as Pd and Ag are the neighbors in the periods of the periodic table while Cu and Ag as well as Ni and Pd belong to the same columns. In the current work the results from the literature and the new result of the authors concerning these four alloy systems are reviewed. Their phase diagrams are essentially different. Partial phase diagrams are presented and discussed with the respect to the formation of quasicrystals. [1] B. Grushko, Heter. Chem. Rev. 1 (1994) 255. [2] B. Grushko, D. Holland-Moritz, K. Bickmann J. Alloys Comp. 236 (1996) 243.