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Open AccessArticle10.3189/s0022143000014738

The Effect of Crystal Size and Dispersed-Solid Inclusions on the Activation Energy for Creep of Ice

Robert W. Baker,W. W. Gerberich-1979-01-01-Journal of Glaciology
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Abstract Steady-state creep-rates of polycrystalline ice were investigated as a function of temperature, grain-size, and inclusion concentration through uniaxial compression in the laboratory. Samples were run at a constant load with the temperature systematically varied between about —5 ° C and —40 ° C. The presence of inclusions inhibits dynamic recrystallization and grain growth; the average crystal size produced by recrystallization is inversely proportional to the inclusion concentration. At temperatures above —8 ° C, creep-rate is enhanced by about a factor of two. This appears to be the result of the combined effects of recrystallization with accompanying grain growth and grain-boundary sliding. Over the temperature range —10 ° C to —40 ° C, the apparent activation energy for creep increases with increasing volume fraction of inclusions. This is apparently due to a thermally activated process which is modified by internal stresses created by the inclusions.

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Abstract Steady-state creep-rates of polycrystalline ice were investigated as a function of temperature, grain-size, and inclusion concentration through uniaxial compression in the laboratory. Samples were run at a constant load with the temperature systematically varied between about —5 ° C and —40 ° C. The presence of inclusions inhibits dynamic recrystallization and grain growth; the average crystal size produced by recrystallization is inversely proportional to the inclusion concentration. At temperatures above —8 ° C, creep-rate is enhanced by about a factor of two. This appears to be the result of the combined effects of recrystallization with accompanying grain growth and grain-boundary sliding. Over the temperature range —10 ° C to —40 ° C, the apparent activation energy for creep increases with increasing volume fraction of inclusions. This is apparently due to a thermally activated process which is modified by internal stresses created by the inclusions.

Keywords

CreepRecrystallization (geology)Grain sizeDynamic recrystallizationActivation energyMaterials scienceCrystalliteAtmospheric temperature range

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