Papers by Keyword: Tilt Boundary

Abstract: The formation conditions of strained (non-equilibrium) triple junctions of grain boundaries were studied by the method of molecular dynamics. It is shown that strained triple junctions, containing excess free volume, mainly forms during crystallization process in the result of "locking" of the liquid phase density at a meeting of the three crystallization fronts and, as a consequence, of the concentration of excess free volume in the triple junction after solidification.

Abstract: We investigated the spatial variation of energy band structure in a SrTiO₃ (001) bicrystal with the (100) 10° tilt boundary before and after the annealing process at 973 K under a vacuum of ~10^-7 Torr and after the subsequent forming process with electrical dielectric breakdown, using electron beam induced current (EBIC) method in the temperature range between 200 and 300K. Although the EBIC contrast at the tilt boundary was weak before and after the annealing, it became visible after the forming process and stronger as the observation temperature decreased to less than 260 K. It was found that the EBIC direction at the tilt boundary is opposite to that in the matrix, i.e. the single crystalline regions of both sides of the tilt boundary. In the matrix, the EBIC increased after the annealing and decreased again after the forming process. We propose energy band structures of the bicrystalline SrTiO₃ after the annealing and after the forming process.

Abstract: Current issues concerning the characterization of grain boundary networks via five-dimensional (5D) grain boundary distributions are considered. A quantitative measure of reliability of such distributions is adapted from conventional texture analysis. Application of the measure shows that with the currently available size of experimental data sets of boundary parameters, only strong components of the boundary distributions can be reliably evaluated. Improvements of the computational part of the analysis are possible if the the binning based on Euler and polar/azimuth angles is replaced by searching the data sets based on a suitably defined distance. Moreover, it is indicated that for textured materials the stereological approach has limited reliability. Finally, it is suggested that coherent twins can be used for estimating experimental errors, and that the distributions cannot be a basis for conclusions about tilt boundaries unless additional restrictions are applied. The approach used in the paper is theoretical with support by computer simulations.