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Showing 1 to 20 of 378 for “"grain boundary"”.
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Grain-Boundary Kinetics And Nonequilibrium Grain-Boundary Structure
… of polycrystalline materials can be described as grain boundary (GB) networks; hence, GBs play major role in a wide-range of polycrystal properties. Control over GB kinetics provides effective means to tailor polycrystal properties through material processing. Understanding and prediction of GB …
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Grain boundary network design
Grain boundaries in polycrystals form a complex interconnected network of intercrystalline interfaces. The crystallographic character of individual grain boundaries and the network structure of the grain boundary ensemble have been experimentally observed to have a strong influence on many …
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Grain Boundary Structure in Alumina
Grain boundary microstructures in alumina ceramics are prone to show glassy phases, faceting, and some fraction of highly coincident twin-related boundaries. These separate phenomena and their inter- actions have been studied in six distinct materials of both commer- cial and experimental origin. …
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Grain boundary mobility of KCl.
Thesis: Sc. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 1976
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Atomistic Study of Grain Boundary Sliding
… In both the creep deformation and damage, grain boundary sliding (GBS) plays a critical role. For example, in ceramics, GBS is the predominant mechanism since dislocation activity is quite suppressed. Although decades of work have gone in understanding GBS, there are several open questions …
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Grain boundary modifications of manganese ferrite
… distinct arcs which were attributed to bulk and grain boundary phenomena. The bulk component was invariant while the grain boundary component varied by less than two orders of magnitude and went through a maximum between 0.2 wt% and 0.4 wt% additions. Only the spinal phase was detected by X-ray …
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Grain Boundary Solute Segregation in Vanadium
… fusion applications, where the presence of grain boundaries can improve mechanical properties and act as a sink for radiation- induced defects. Solutes with a thermodynamic preference to segregate to grain boundaries can stabilize them, making this a prime consideration for alloy design, but …
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Grain boundary self-diffusion in sodium chloride
… of ²²sodium and ³⁶chlorine along tilt and twist grain boundaries in pure and calcium chloride doped sodium chloride bicrystals was investigated. No enhanced diffusion of ²²sodium along the grain boundaries was observed. Between 400°C and 500°C the chlorine grain boundary diffusion parameter, D'Δ, …
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Topological analysis of the grain boundary space
Grain boundaries and their networks have a profound influence on the functional and structural properties of every class of polycrystalline materials and play a critical role in structural evolution and phase transformations. Recent experimental advances enable a full crystallographic …
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Grain boundary precipitation in aluminum alloy 7075
… related to the distribution of precipitates on grain boundaries. In particular, an increase in the spacing of grain boundary precipitates has been correlated with an increase in the resistance to stress corrosion cracking [1]. In this study, three approaches to heat treating aluminum alloy 7075 …
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Grain boundary engineering in additively manufactured polycrystalline materials
… components with minimal material waste. Grain boundary engineering (GBE) is a well-established approach for enhancing mechanical properties and reducing corrosion susceptibility in polycrystalline materials by increasing the fraction of low-energy grain boundaries. However, conventional …
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The Spectral Model of Grain Boundary Solute Segregation
The segregation of solute atoms at grain boundaries (GBs) can profoundly impact the structural properties of metallic alloys, and induce effects that range from strengthening to embrittlement. And, as such, the control of solute segregation is emerging as an alloy design tool, uses of which include …
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Crystallographically consistent percolation theory for grain boundary networks
Grain boundaries are known to play a role in many important material properties including creep resistance, ductility and cracking resistance. Although the structure and properties of individual boundaries are important, the overall behavior of the material is determined largely by the connectivity …
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Recovering Grain Boundary Inclination Parameters Through Oblique Double-Sectioning
A method for the retrieval of grain boundary inclination parameters of the grain boundary character distribution by oblique double-sectioning is proposed. The method, which is similar to the recovery of the orientation distributions from sets of incomplete pole-figures, is described along with a …
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Josephson Interferometry Measurements in High-Tc Grain Boundary Junctions
We study Josephson junctions formed at grain boundary interfaces in the high-Tc cuprate materials. The inherent properties of these Josephson junctions depend strongly on the pairing symmetry and the electronic structure at the interface and can be used to determine the pairing symmetry as well as …
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Phase-and-Defect Diagrams for Polycrystalline Grain Boundary Segregation
… solute and segregated atoms, dislocations, and grain boundaries. In recent years, a push has been made to treat defects as “defect states” in a manner analogous to bulk phases so they can be analyzed alongside existing bulk equilibrium phase diagrams – a treatment I refer to here as …
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Photovoltaic modeling and grain boundary recombination in poly-silicon
… The second part of the dissertation deals with grain boundary (GB) recombination, passivation, and characterization. A simple GB model is developed, and an expression for the GB barrier height under illumination is derived by introducing a quasi Fermi-function. By using this model, the …
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Grain boundary studies in ordered intermetallic compound Ni3 Al
Theoretical and experimental studies of grain boundary structures were carried out to understand the grain boundary properties of Ni₃Al. Using various techniques of transmission electron microscopy, the geometry of grain boundaries was determined from a number of grain boundaries to obtain a …
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Grain boundary networks in RABiTS based YBa2Cu3O7[-delta] coated conductors
… leads to the formation of a YBa2Cu3O7[-delta] grain boundary network and limits the critical current density of the samples. In order to study this limitation, critical current measurements were performed on the prepared samples at different temperatures and magnetic fields, detecting a …
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