Roessiger J., Bons P.D., Griera A., Jessell Mark, Evans L., Montagnat M., Kipfstuhl S., Faria S.H., Weikusat I. (2011). Competition between grain growth and grain-size reduction in polar ice. Journal of Glaciology, 57 (205), p. 942-948. ISSN 0022-1430.
Titre du document
Competition between grain growth and grain-size reduction in polar ice
Roessiger J., Bons P.D., Griera A., Jessell Mark, Evans L., Montagnat M., Kipfstuhl S., Faria S.H., Weikusat I.
Source
Journal of Glaciology, 2011,
57 (205), p. 942-948 ISSN 0022-1430
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.
