Superordering in Ni-rich and Ni-poor decagonal Al-Co-Ni phases

Hradil, K.; Weidner, Eveline; Neder, R. B.; Frey, Friedrich und Grushko, B. (1999): Superordering in Ni-rich and Ni-poor decagonal Al-Co-Ni phases. In: Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties, Bd. 79, Nr. 8: S. 1963-1976

Abstract

Single-crystal X-ray diffraction was carried out on a decagonal Ni-rich phase in the Al-Co-Ni system with a nominal composition of Al72.5Co11Ni16.5. Apart from sharp Bragg reflections, satellite scattering was observed in Al72.5Co11Ni16.5 which is different from the satellite scattering observed in a Ni-poor phase with nominal composition Al72.5Co16.5Ni11. The two types of superorder scattering are interpreted in an unified way by periodic order superimposed on the quasiperiodic averaged substructure. This periodic regimes have a limited correlation length (short-range ordering). While the modulation period stays almost constant over a wide range of compositions in these decagonal alloys, the modulation vector is rotated by π/10 if passing from Ni-rich (S satellites) to Ni-poor (C satellites) compositions. Arguments are given in favour of this interpretation which is also supported by computer simulations.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Geowissenschaften > Department für Geo- und Umweltwissenschaften > Kristallographie und Materialwissenschaft
• Themengebiete: 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie
• Sprache: Englisch