Shock waves in quasicrystals

Shock waves represent a heavy load on materials. In solids, they create a variety of defects like shear bands or crystal domains. Waves of large amplitude may destroy the structural order completely. We study shock waves in an Al-Cu-Li-type model quasicrystal, in a closely related crystal structure, the C15 (MgCu2) Laves phase, and in an amorphous solid. If we take the slightly different composition and binding energy into account, we find that the sound velocity in all the structures is about the same. If the shock waves are weak, only point defects occur. With increasing intensity, we observe broad defect bands in the crystal and the quasicrystals, if the cross section of the sample is large enough. Otherwise the structure looks like an amorphous state. At large shock wave intensities, the shock front velocity approaches the universal material-independent behavior. The structure is destroyed completely in this regime. The crystal occurs to be slightly more stable than the quasicrystal which means that defects and destruction of the sample are found at higher shock wave intensities. (C) 2000 Elsevier Science B.V. All rights reserved.