ELASTIC PROPERTIES OF QUASI-CRYSTALS

The elastic properties of several families of quasicrystals have been measured between 0.010 and 100 K. Their speed of sound varies linearly with temperature above 4 K, and their internal friction approaches a temperature-independent value below 4 K. These two quantities are prop ortional to each other even when the damping is much smaller than in a ny amorphous solid. It is concluded that the elastic properties of qua sicrystals span the range from nearly perfect crystals to amorphous so lids.