The crystal structure of a γ-(Al-Cu-Ru-Si) cubic phase (Al55.1Cu14.6Ru20.2Si10.1), considered to be closely related to that of the Al-Cu-Ru icosahedral quasicrystal, has been determined by single-crystal X-raydiffraction. The atomic model, refined to a final R value of 0.0346, has about262 atoms with an atomic ratio of Al66.3Cu13.5Ru19.8in a cubic unit cell with alattice constant a = 1.538 0(2) nm and the space group Fm3. The fundamentalstructure is characterized by a sc arrangement of dodecahedral atom clusters withan interval of 0.77nm, which corresponds to a lattice constant of a 1/0 cubicapproximant phase for the icosahedral quasicrystals. The chemical ordering ofthe constituents in the dodecahedral cluster produces a superstructure with alattice constant twice that of a 1/0 cubic approximant phase.
ASJC Scopus subject areas
- Condensed Matter Physics