Grain boundary plane distribution and its potential correlation with magnetic properties in hexagonal RCo5 permanent magnets

The crystallographic texture in permanent magnets should cover not only texture of crystals, but also texture between crystals.

Incompatibility Stresses and Lattice Rotations Due to Grain Boundary Sliding in Heterogeneous Anisotropic Elasticity

Non-uniform grain boundary sliding can induce strain and rotation incompatibilities at perfectly planar interfaces. Explicit analytic expressions of stress and lattice rotation jumps are thus derived at a planar interface in the general framework of heterogeneous anisotropic thermo-elasticity with plasticity and grain boundary sliding. Both elastic fields are directly dependent on in-plane gradients of grain boundary sliding. It is also shown that grain boundary sliding is a mechanism that may relax incompatibility stresses of elastic, plastic and thermal origin although the latter are not resolved on the grain boundary plane. This relaxation may be a driving force for grain boundary sliding in addition to the traditionally considered local shears on the grain boundary plane. Moreover, the obtained analytic expressions are checked by different kinds of bicrystal shearing finite element simulations allowing grain boundary sliding and where a pinned line in the interface plane aims at representing the effect of a triple junction. A very good agreement is found between the analytic solutions and the finite element results. The performed simulations particularly emphasize the role of grain boundary sliding as a possible strong stress generator around the grain boundary close to the triple line because of the presence of pronounced gradients of sliding.

Structural and electronic properties of defects at grain boundaries in CuInSe2

Octet rule violation near the grain boundary plane is common in Σ3 grain boundaries, with important structural and electronic implications.

Reconstruction of α–Iron 〈100〉 Symmetric Tilt Grain Boundaries Σ17(410) and Σ13(510)

A detailed numerical study on structure of symmetric tilt grain boundaries in α-iron is presented. The study is focused on structural and energetic optimization of 〈100〉 grain boundaries Σ5(210), Σ5(310), Σ17(410) and Σ13(510). Particular attention is given to grain boundary reconstruction, which is characterized by increased atomic density in grain boundary plane compared to bulk. The results of our numerical experiments significantly improved our knowledge about the migration of atoms between planes perpendicular as well as parallel to GB plane as an essential part of grain boundary reconstruction.