Internal Friction of Synthetic Quartz

Abstract

Internal friction of twenty six specimens of synthetic quartz was measured at room temperature using the composite oscillator method. Specimens were cylinders, axes of which lay in the crystallographic YZ-plane and made various angles extending from −35° to +40° with the Y-axis. Synthetic quartz had usually smaller values of the internal friction than natural quartz. The internal friction of specimens parallel or nearly parallel to the Y-axis was almost independent of the strain amplitude, while that of specimens inclined to the axis at high angles showed noticeable amplitude-dependence. The orientation-dependence of the values of the internal friction could be well explained by the theory of dislocation damping. The dislocation density in synthetic quartz was estimated to be 10²–10³ cm ⁻², being about one hundredth of the density in natural crystals. Effect of X-irradiation on the internal friction of quartz was also studied for both synthetic and natural ones.