X-ray diffraction study on uniformly oriented quasicrystals

X-ray diffraction results on several uniformly oriented quasicrystals of an Al-Li-Cu alloy are reported. By means of long exposed monochromatic Laue and precession photographs, we confirm the parity rules for a primitive icosahedral quasilattice. Moreover, for the first time, complex diffuse scattering related to the icosahedral symmetry has been observed. Spherical shells of diffuse scattering appear in reciprocal space : the centres of the most intense shells are located on the five-fold axes.