Dislocation nucleation and multiplication in synthetic quartz: Relevance to water weakening

摘要: Recent observations suggest that the water-related defects associated with so-called water weakening of single crystals “wet” synthetic quartz are high-pressure clusters molecular water. The microstructures which evolve in these during both creep and constant strain-rate experiments by heating alone were observed TEM show act as highly efficient sources glissile dislocations must be nucleated before plastic flow can induced. These microstructural observations, together simple microdynamical concepts based on Orowan equation, used to rationalize behaviour all main features stressstrain curves a wide range bulk water-contents, without postulating any direct influence dislocation glide. It is proposed, therefore, relatively low yield stress primarily due ease fresh nucleated, rather than an enhanced glide hydrolysed generally assumed most models weakening.