Large angle convergent beam electron diffraction determinations of dislocation Burgers vectors in synthetic stishovite

Polycrystalline stishovite, synthesized in a multi-anvil apparatus at 15 GPa and 1200 degrees C, contains numerous dislocations. The microstructures of the recovered material have been investigated using Transmission Electron Microscopy (TEM). The Burgers vectors of the dislocations were determined using Large Angle Convergent Beam Electron Diffraction (LACBED), We find that < 100 >, < 001 >, < 110 > and < 101 > dislocations were activated in the stishovite during the synthesis experiments. Dislocation microstructures, indicative of dislocation glide, suggest that plastic deformation occurred during quench. Subgrain boundaries that are present in some grains indicate that some recovery occurred. As recovery is unlikely during quench, deformation also occurred during synthesis.