%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Roessiger, J.
%A Bons, P.D.
%A Griera, A.
%A Jessell, Mark
%A Evans, L.
%A Montagnat, M.
%A Kipfstuhl, S.
%A Faria, S.H.
%A Weikusat, I.
%T Competition between grain growth and grain-size reduction in polar ice
%D 2011
%L PAR00008306
%G ENG
%J Journal of Glaciology
%@ 0022-1430
%M ISI:000296118700017
%N 205
%P 942-948
%U https://www.documentation.ird.fr/hor/PAR00008306
%V 57
%W Horizon (IRD)
%X 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.
%$ 062