Strain heterogeneities at the ductile to brittle transition; a case study on ice

Abstract

Abstract. This paper presents, for the first time, the evolution of local strain fields around intragranular cracking in polycrystalline ice, at the onset of tertiary creep. Owing to the high homologous temperature conditions and relatively low compressive stress applied, stress concentration at crack tips is relaxed by plastic mechanisms associated with dynamic recrystallization. Strain field evolution followed by Digital Image Correlation indirectly shows the redistribution of stresses during crack opening, but also driven by crack tip plasticity mechanisms and recrystallization. Such redistribution induces modifications in the local strain deformation bands, and crack closure during deformation. A strong interaction between cracking and dynamic recrystallization is therefore evidenced at the ductile to brittle transition in ice deformed at high homologous temperature.