Original paper

Continuous description of grain boundaries using crystal defectfields: the example of a {3 1 0}/[0 0 1] tilt boundary in MgO

Sun, Xiao-Yu; Cordier, Patrick; Taupin, Vincent; Fressengeas, Claude; Karki, Bijaya B.

European Journal of Mineralogy Volume 29 Number 2 (2017), p. 155 - 165

published: Apr 1, 2017

DOI: 10.1127/ejm/2017/0029-2609

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Abstract

Continuum dislocation/generalized-disclination modelling of a MgO {3 1 0}/[0 0 1] tilt boundary is proposed by using an atomistic-to-continuum crossover method. Using the relaxed and un-relaxed atomic positions obtained from first-principles simulations, calculation of the displacement, distortion (strain and rotation), curvature and second-order distortion fields is performed in the boundary area. The dislocation and disclination density fields are used to smoothly describe the discontinuities in the displacement and rotation fields across the boundary. In addition, a generalized-disclination density tensor field is introduced to reflect shear and stretch discontinuities across the boundary. This continuous model provides new mechanical insights into the structure of MgO grain boundary, as well as a basis for coarse-grained representations of the polycrystalline structure.

Keywords

mgoatomistic simulationgrain boundarygeneralized disclinationdislocationcontinuum mechanics