Interaction between dislocations and precipitated water bubbles during high temperature creep of quartz

The modes of interaction between dislocations and precipitated water bubbles in quartz are discussed. It is shown that dislocations may be locally anchored by bubbles, but are able to break away under the action of applied stress. To escape, dislocations pinned by bubbles must bow to equilibrium curvature. It was observed that escape via thermal activation alone was not readily possible; however, unpinning of the dislocation through pipe diffusion was found to be possible if the dislocation could drag the bubbles under applied stress. This could result in very small strains leading to a microcreep rate linearly dependent on stress and independent of the concentration of bubbles.