Pressure-induced transformation plasticity of H2O ice

Transformation plasticity is a deformation mechanism which occurs juring ph ase transformation of an externally stressed material. Pressure-induced tra nsformation plasticity of ice could be relevant to the neology of the moons of the outer solar system, and has long been postulated to occur in olivin e in the earth's interior. Ln the present work, ice specimens were subjecte d to isostatic pressure cycling between 0 and 300 MPa to induce reversible polymorphic transformation between ice I and LI at 230 K. When a small unia xial compressive stress was applied during cycling, the specimens exhibited a compressive strain las large as 18.5% after a single cycle) proportional to the applied stress, in agreement with observations and theory for trans formation plasticity of metals induced by polymorphic thermal cycling.