INFLUENCE OF PRESSURE ON GRAIN BOUNDARY MIGRATION IN ICE

GUZMAN P.; DI PRINZIO, CARLOS LEONARDO; NASELLO, OLGA BEATRIZ

Newfoundland Canada

Congreso; PCI 2002 Physics and Chemistry of Ice 2002; 2002

Physics and Chemistry of Ice 2002

The study of grain boundary (GB) movement in bicrystalline samples, exhibiting the Sun and Bauer configuration, has been of great usefulness to investigate de influence of the individual factors that control this phenomenon. The goal of the present work has been to use this method to undertake the study of pressure on grain boundary movement in ice. The samples studies consist of pure and 4 10-9 M ClK-doped ice bicrystals with  crystalline misorientation, annealed at –5ºC  and –20ºC under atmospheric pressure (0.1 MPa) and hydrostatic pressure of 10 MPa. Results show that the grain boundary is dragged by the groove formed at the intersection of the GB with the surface, this effect being more manifest at higher pressures. They also indicate that the inclusion of a ClK increases GB mobility even at concentrations as low as 4 10-9 M, and that, in samples under pressures of 10 Mpa, GB movement can be up to 2 or 3 times larger than in samples under atmospheric pressures. Also, pressure has been shown to favour the formation of surface groove, which is a clear evidence of the increase of the surface diffusion coefficient with pressure. Therefore, due to their influence on GB mobility as well as on ice surface, the inclusion of ClK and the pressure are shown to raise GB-boundary movement in bicrystalline ice samples.