Stable 10-Fold Facetted Single Grain Decagonal Quasicrystals of Al sub (65) Cu sub (15) Co sub (20).

We report stable Al sub (65) Cu sub (15) Co sub (20) decagonal quasicrystals which exhibit facetted columnar morphology. The column axis is along the 10-fold direction, and it is facetted by the ten two-fold planes. Facetted single grains, several millimeters in size were grown and characterized. Peritectic growth is fastest along the periodic 10-fold axis and slowest along the nucleation controlled, quasiperiodic 2-fold directions. Single crystal x-ray scattering verifies the two-dimensional quasiperiodic structure. The two-dimensional quasicrystalline structure is defect free on a length scale of 2000angstroms and is layered with a thickness of 8.26angstroms. PAC NO. 61. 50.Jr; 61.55.Hg; 61.10.-i; 61.50.Cj.