Abstract
Abstract
Highlights
In the Earth’s mantle, with increasing depth, pressure increases rapidly, reaching values as high as 136 GPa at the base of the mantle.[1]. These ultrahigh pressures have profound implications on the rheology of the Earth’s constituents that can be quite different from that observed at ordinary pressure
Within a recent elastoplastic framework proposed by Fressengeas et al.[16] and Acharya–Fressengeas,[17] it was shown that dislocation, disclination and generalized-disclination (g-disclination) density fields were appropriate mathematical objects for a consistent continuous description of the atomic defected structures, energetics, and dynamics of grain boundary (GB).[18,19,20]
By using an atomistic-to-continuum crossover method, we provide a continuous description of the defect density fields within a MgO {310}/[001] tilt GB at different pressures
Summary
In the Earth’s mantle, with increasing depth, pressure increases rapidly, reaching values as high as 136 GPa at the base of the mantle.[1]. Within a recent elastoplastic framework proposed by Fressengeas et al.[16] and Acharya–Fressengeas,[17] it was shown that dislocation, disclination and generalized-disclination (g-disclination) density fields were appropriate mathematical objects for a consistent continuous description of the atomic defected structures, energetics, and dynamics of GBs.[18,19,20] For instance, disclinations were found to decorate GBs in minerals and were proposed as good candidates at providing plastic accommodation mechanisms in dislocation slip-deprived rocks in the upper mantle.[19] Here we focus on how pressure influences the dislocation, disclination, and g-disclination structures of a MgO {310}/[001] tilt GB. The dislocation, disclination and g-disclination density fields are calculated to study the influence of pressure on the defected structure of GBs, in terms of discontinuities of elastic displacement, rotation, and strain fields
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