Interactions between dislocations and precipitated water bubbles in quartz were studied. It was shown that dislocations could be locally anchored by bubbles, but were able to break away under an applied stress. In order to escape, dislocations that were pinned by bubbles had to bow out to their equilibrium curvature. It was observed that escape via thermal activation alone was not easily achieved. However, unpinning of the dislocation via pipe diffusion was found to be possible if the dislocation could drag the bubbles under an applied stress. Very small strains then led to a micro-creep rate which was linearly dependent upon the stress and was independent of the bubble concentration.

A.Ayensu: Journal of Materials Science, 1997, 32[1], 123-8