Morphology and microstructure of Al-Li-Cu quasicrystals.

Solidification microstructure of the stable icosahedral Al sub (5.1) Li sub 3 Cu alloy is studied by scanning electron microscopy. Free surface solidification morphology is found to consist of heavily facetted dentrites with the shape of a triacontahedra. Quasicrystals grow fastest along the five- fold direction and the slowest growing two-fold planes give rise to the facetted morphology. An epitaxial relationship between cubic and quasicrystalline phases is directly observed.