Continuous description of the atomic structure of grain boundaries using dislocation and generalized-disclination density fields. (February 2016)

• Record Type: Journal Article
• Authors: Sun, Xiao-Yu; Taupin, Vincent; Fressengeas, Claude; Cordier, Patrick
• Is Part Of: International journal of plasticity. Volume 77(2016:Feb.)
• Page Start: 75
• Page End: 89
• Publication Date: 2016-02
• Subjects: A. Grain boundaries -- A. Dislocations -- Generalized-disclinations -- C. Finite differences; Plasticity -- Periodicals; Plasticité -- Périodiques; Plasticity; Periodicals; 620.11233
• DOI: 10.1016/j.ijplas.2015.10.003
• Languages: English
• ISSNs: 0749-6419

Abstract

Abstract: An atomistic-to-continuum method is developed to derive dislocation, generalized-disclination density fields and the associated elastic strain, rotation, curvature and second-distortion fields from the atomic structure of grain boundaries. From the relaxed and un-relaxed atomic positions, calculation of the transformation gradient feeds a mechanical framework, where discontinuities of the lattice elastic displacement and distortion (rotation and strain) are captured by smooth incompatible strain and second-distortion fields associated with the dislocation and generalized-disclination density fields, respectively. The method is applied to a copper symmetrical tilt boundary as obtained from molecular dynamics simulations. The core structure of the boundary is found to contain edge dislocations and dipoles of generalized-disclinations, including standard wedge-disclination dipoles. The latter reflect in particular localized shear and stretch discontinuities across the interface, in addition to the overall rotation discontinuity. Highlights: An atomistic-to-continuum method is developed to model grain boundaries. The method is applied to a copper boundary as obtained from atomistic simulations. The grain boundary is found to contain edge dislocations and disclination dipoles. Shear and stretch discontinuities can be reflected by generalized-disclinations.