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Titre du document / Document title

Effects of impurities and their redistribution during recrystallization of ice crystals

Auteur(s) / Author(s)

ILIESCU D. (1) ; BAKER I. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Thayer School of Engineering, Dartmouth College, Hanover New Hampshire 03755-8000, ETATS-UNIS

Résumé / Abstract

In order to examine the effects of solutes on recrystallization and subsequent grain growth in ice, both doped and undoped ice single crystals were extruded through a 120° equal-channel angular extrusion jig, in order to impart a large shear strain (∼1.15). Upon subsequent annealing at -3°C, the original single crystals recrystallized, in most cases to a new single crystal with a different orientation. Increasing the solute concentration (for H2SO4 to ∼200-300 ppb, and for NaCI, KCI and MgSO4 to >5 ppm) was found to significantly retard the growth and possibly, for H2SO4-doped ice, the nucleation of new grains in the strained ice single crystals. This is indicative of how soluble impurities can retard grain growth in ice cores. It was also found that the migrating grain boundaries surrounding the newly formed grains contained large concentrations of impurities, often observed as filaments. These could have formed by the grain boundaries sweeping up impurities from the lattice into the boundary or by their diffusion to the boundary - mechanisms whereby impurities could be concentrated into the grain boundaries in ice cores - although the latter mechanism seems unlikely since it would require very high diffusion rates.

Revue / Journal Title

Journal of Glaciology    ISSN  0022-1430   CODEN JOGLAO 

Source / Source

2008, vol. 54, no185, pp. 362-370 [9 page(s) (article)] (1 p.)

Langue / Language

Anglais

Editeur / Publisher

International Glaciological Society, Cambridge, ROYAUME-UNI  (1947) (Revue)

Mots-clés anglais / English Keywords

Limiting factor

;

Concentration effect

;

microstructures

;

Grain boundary migration

;

Grain growth

;

recrystallization

;

experimental studies

;

Ice crystals

;

Impurity effect

;

Polar region

;

drill cores

;

Historical reconstruction

;

Investigation method

;

paleoclimatology

;

Mots-clés français / French Keywords

Facteur limitant

;

Effet concentration

;

Microstructure

;

Migration joint grain

;

Croissance grain

;

Recristallisation

;

Etude expérimentale

;

Cristal glace

;

Effet impureté

;

Zone polaire

;

Carotte

;

Reconstruction historique

;

Méthode étude

;

Paléoclimatologie

;

Mots-clés espagnols / Spanish Keywords

Factor limitante

;

Efecto concentración

;

Microestructura

;

Migración limite grano

;

Crecimiento grano

;

Recristalización

;

Cristal hielo

;

Efecto impureza

;

Zona polar

;

Testigo

;

Reconstrucción histórico

;

Método estudio

;

Localisation / Location

INIST-CNRS, Cote INIST : 5524, 35400019801571.0170

Nº notice refdoc (ud4) : 20435356



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