Papers by Keyword: Bi-Crystal

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Authors: Christoph Günster, Dmitri A. Molodov, Günter Gottstein
Abstract: The results of investigations of magnetically driven grain boundary migration in high purity (99.995%) zinc bicrystals are presented. In-situ measurements were conducted by means of a specially designed and fabricated polarization microscopy probe. The migration of planar tilt grain boundaries with various misorientation angles in the range between 60° and 90° was studied. The absolute grain boundary mobility and its temperature dependence was measured in the regime between 330°C and 415°C and the corresponding migration activation parameters were determined. The results revealed that there is a pronounced misorientation dependence of grain boundary mobility in the investigated angular range. The migration activation enthalpy was found to vary between 1.18 eV and 2.15 eV. The obtained activation parameters comply with the compensation law, i.e. the migration activation enthalpy changes linearly with the logarithm of the pre-exponential factor.
Authors: Tatiana Gorkaya, Thomas Burlet, Dmitri A. Molodov, Günter Gottstein
Abstract: A novel set-up developed to continuously observe and measure stress driven grain boundary migration is presented. A commercially available tensile/compression SEM unit was utilized for in-situ observations of mechanically loaded samples at elevated temperatures up to 850°C by recording orientation contrast images of bicrystal surfaces. Two sample holders for application of a shear stress to the boundary in bicrystals of different geometry were designed and fabricated. The results of first measurements are presented.
Authors: Dmitri A. Molodov, U. Czubayko, Günter Gottstein, Lasar S. Shvindlerman
Authors: Alexei Vinogradov, S. Hashimoto, Sei Miura, A. Vikarchuk, M. Nadtochiy
Authors: Václav Paidar, Pavel Lejček, M. Polcarová, J. Brádler, Alain Jacques
Abstract: Grain boundary motion was studied in situ at elevated temperatures by x-ray topography using synchrotron radiation. In addition to the position of grain boundary, other crystal defects that may interact with the moving boundary were observed simultaneously. Two types of bicrystals with the [001] rotation axis were selected for the experiments, the first one with a high coincidence S5 misorientation of about 37° and the other one with no coincidence of two crystals for the misorientation of 45°. The geometrical differences between chosen bicrystals are examined and attention is also paid to faceting – local orientations of the boundary plane.
Authors: Yuichi Ikuhara, T. Watanabe, T. Saito, H. Yoshida, Taketo Sakuma
Authors: Naoya Shibata, Fumiyasu Oba, Takahisa Yamamoto, Yuichi Ikuhara
Abstract: In this paper, we characterized atomic structure of a Σ = 3, [110]/{112} grain boundary in a yttria-stabilized cubic zirconia bicrystal. High-resolution transmission electron microscopy (HRTEM) clearly revealed that the grain boundary migrated to form {111}/{115} periodical facets, although the bicrystal was initially joined so as to have the symmetric straight boundary plane of {112}. Atomic-scale process for the facet growth could be modeled by the continuous flippings of atoms at the boundary core.
Authors: M. Polcarová, Alain Jacques, J. Brádler, F. Vallino, J. Gemperlová, A. George
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