Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 13 of 13 for “"Grain Boundary Segregation"”.
-
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 …
-
Variations in grain boundary segregation for nanocrystalline stability and strength
… mainly due to temperature related growth. Grain boundary segregation is one way in which materials can keep nano length-scale grains. This process involves metal alloys that preferentially segregate the alloying material to the grain boundaries, potentially leading to Grain Boundary …
-
Segregation and embrittlement in metallic interfaces : bounds, models, and trends
Metals with grain sizes below 100 nanometers exhibit remarkable hardness [1], wear resistance [2], and superplastic forming behavior [3], in addition to changes in many other properties. These materials are thus of technological interest as structural materials. However, the excess free energy …
-
Mechanical Property Evolution and Thermal Remediation of Aluminum Magnesium 5xxx Alloys Following Low and Intermediate Temperature Thermal Exposure
… resistance, etc.) and microstructures (e.g. grain boundary segregation, grain boundary precipitation, etc.) with thermal exposure at these (and lower) temperatures has significant practical implications for various structural applications. The effects of thermal remediation treatments are …
-
An analytic solution for magnetization distribution in multigrain ferromagnetic materials in an applied magnetic field
… by the variation in anisotropy direction from grain to grain as well as the changes in ferromagnetic parameters at grain boundaries and other defect regions. For example, transmission electron microscopy results show that chromium segregation occurs at the grand boundaries in CoCrTa films, …
-
Application of Disorder-Induced Melting Concept to Fracture
… melting concept to an existing fracture problem: segregation-induced intergranular embrittlement. This is accomplished in the nickel-sulfur system by a comparison of the composition dependencies for polymorphous melting and intergranular fracture. The composition dependence for polymorphous …
-
Stability of nanostructured : amorphous aluminum-manganese alloys
… incorporation level. The manganese exhibits grain boundary segregation in the Al-Mn solid solution in the as-deposited condition, which contributes to enhanced stability of the nanostructure. The grain boundary properties of the nanostructured alloys were studied via three dimensional atom …
-
Design of stable nanostructure configurations in ternary alloys
… alloys, which possess a large volume fraction of grain boundaries at elevated temperatures, is a promising route to high yield strength materials. Previous studies have focused on alloying by selecting solute elements that segregate at grain boundaries to stabilize the nanostructure. A selection …
-
Enhancing stability of powder-route nanocrystalline tungsten-titanium via alloy thermodynamics
Improvement in material properties as a result of grain size refinement to the nanoscale is often limited by an inherent tendency of these nanostructured materials to coarsen especially at the high temperatures required for processing. The structural instability stems from a large volume fraction …
-
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 …
-
Grain boundary chemistry and morphology of heavily doped cerium dioxide
… of the cubic fluorite structure, in which grain boundaries are known to limit the overall ionic conductivity of polycrystals. Measurements of grain boundary segregation of the aliovalent dopants Gd3+ and Ta5+ in heavily doped ceria have been made using a Vacuum Generators HB603 scanning …
-
Polycrystalline Grain Boundary Solute Segregation at Finite Sizes and Temperatures
… alloys. With this concept, solute segregation at grain boundaries can be employed as a defect design tool to stabilize such systems against coarsening. However, the understanding and availability of grain boundary data are still limited for polycrystals that contain a profuse …
-
Atomistic Modeling of Defect Energetics and Kinetics at Interfaces and Surfaces in Metals and Alloys
Planar defects such as free surfaces and grain boundaries in metals and alloys play important roles affecting many material properties such as fracture toughness, corrosion resistance, wetting, and catalysis. Their interactions with point defects and solute elements also play critical roles on …