Competition between grain growth and grain-size reduction in polar ice
Roessiger, Jens
Bons, Paul D.
Griera, Albert
Jessel, Mark W.
Evans, Lynn
Montagnat, Maurine
Kipfstuhl, Sepp
Faria, Sergio H.
Weikusat, Ilka
57, 205: 942 - 948
Roessiger, Jens; Bons, Paul D.; Griera, Albert; Jessel, Mark W.; Evans, Lynn; Montagnat, Maurine; Kipfstuhl, Sepp; Faria, Sergio H.; Weikusat, Ilka, 2011: Competition between grain growth and grain-size reduction in polar ice. In: Journal of Glaciology, Band 57, 205: 942 - 948, DOI: 10.23689/fidgeo-2637.
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Static (or ‘normal’) grain growth, i.e. grain boundary migration driven solely by grain
boundary energy, is considered to be an important process in polar ice. Many ice-core studies report a
continual increase in average grain size with depth in the upper hundreds of metres of ice sheets, while
at deeper levels grain size appears to reach a steady state as a consequence of a balance between grain
growth and grain-size reduction by dynamic recrystallization. The growth factor k in the normal grain
growth law is important for any process where grain growth plays a role, and it is normally assumed to
be a temperature-dependent material property. Here we show, using numerical simulations with the
program Elle, that the factor k also incorporates the effect of the microstructure on grain growth. For
example, a change in grain-size distribution from normal to log-normal in a thin section is found to
correspond to an increase in k by a factor of 3.5.
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