Measurement of glasslike and crystalline elasticity in quasicrystals

We have measured the Young's modulus and internal friction of several families of aluminum-based quasicrystals from 0.01 to 300 K and from 200 Hz to 8 kHz with a vibrating-reed technique. In the metastable aluminum--transition-metal quasicrystals we see a unique large linear temperature dependence of the internal friction in the 1--100-K range; this is one of the very few measured properties of quasicrystals that differ from metallic glasses or alloys. We do not see the large linear dependence in quasicrystals from the stable families, providing an observable difference in the physical properties of the stable and metastable families. We see glassy behavior in some of the quasicrystals that is as large as that observed in metallic glasses. Finally, we will present low-temperature speed-of-sound data that cannot be explained by standard models of glasses and alloys.