New stable icosahedral quasicrystalline phase in the Sc-Cu-Zn system

摘要

Stable icosahedral quasicrystals have been synthesized in the Sc-Cu-Zn system by quench-and-anneal or in-situ filtration methods. These have a composition near Sc_(16.2(3))Cu_(12.3(3))Zn_(71.5(6)) at 480 ℃ with a quasilattice constant of 4.995 6(7) A determined by the Elser method from a single-phase Guinier pattern. An electron diffraction study confirms that the icosahedral quasicrystals have a primitive lattice. Cuboctahedral single crystals with dimensions up to 100 μm have been grown by melt-spinning techniques. A cubic approximant phase Sc14.2Cu10.3Zn75.5 (ScCu0.73Zn5.33) with a concordant lattice constant lies nearby.