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 20 of 43 for “"stacking faults"”.
-
Mesoscale Models for Stacking Faults, Deformation Twins and Martensitic Transformations: Linking Atomistics to Continuum
Finally, we extend the present work to martensitic transformations and determine the energy pathway for B2→B19 transformation in NiTi. Based on our ab initio DFT calculations, we propose a combined distortion-shuffle pathway for B2→B19 transformation in NiTi. Our results indicate that in …
-
A study of the mean-square displacement amplitudes of T and O atoms in framework silicates and aluminosilicates: evidence for rigid TO bonds, order, disorder, twinning and stacking faults in crystals
The mean-square displacement amplitudes (MSDA) of the tetrahedral cations Si and Al are compared to the MSDA of their coordinated O atoms in framework silica polymorphs and aluminosilicate structures. Criteria are established which indicate order, structural disorder or substitutional disorder in a …
-
Structural Characterisation of Heteroepitaxial Zincblende Gallium Nitride
… zincblende GaN lattice. Defects, including stacking faults and dislocations, are found to relax the heteroepitaxial zincblende GaN film in both nucleation layers and epilayers. Miscut of the 3C-SiC/Si substrate, used to avoid the formation of antiphase domains, results in the preferential …
-
Photoluminescence Measurement on Low-temperature Metal Modulation Epitaxy Grown GaN
… GaN material has been shown to be the result of stacking faults. We believe this peak in the MME GaN is also the result of stacking faults. In droplets were used as a surfactant to improve the quality of MME grown GaN. By comparing the PL signal from samples with and without In surfactant, it was …
-
Optical and Spin Properties of Defect-Bound Excitons in Semiconductors
… Lastly, we investigate excitons bound to stacking faults, a common extended semiconductor defect, finding ultra-homogeneous linewidths and a giant exciton dipole moment. These feature imply that stacking faults could potentially be useful for studying many-body physics in …
-
Computational Modeling Of High-Performance Nickel-Metal Hydride Battery Materials
… to structure and electrochemical performance. Stacking faults direct interrupt (h0l) plane periodicity of nickel hydroxide materials, and through Rietveld refinement and DIFFaX modeling of the different types of stacking faults, the evolution of the stacking faults was tracked over …
-
On the plastic deformation behaviour of nickel-based superalloys: low cycle fatigue and stress orientation effects
… of loading orientation on the propagation of stacking faults. A series of experimental and modelling techniques are employed throughout the thesis. Low cycle fatigue is investigated with the motivation of understanding how slip bands form and develop prior to crack initiation. Electron …
-
Carbon Chemistry Of Giant Impacts
… grains comprised apographitic. platy grains with stacking faults, etching and graphite intergrowths together with elongate skeletal grains with preferred orientations to the individual crystallites. Thermal annealing of stacking faults and surface features was also detected. Stepped combustion …
-
Interfacial effects on the structure of thin metal films
… wires can exhibit unusual properties such as stacking faults and electronic topological phase transitions due to the interfacial modulation. We report a study of Ag films grown on an array of atomic In chains on . Prior STM studies have suggested an array of stacking faults in the Ag films …
-
Synthesis and characterization of nanocrystalline alloys in the binary Ni-Co system/
… to refine the grain structure. Owing to the low stacking fault energy of Co, many of the alloy deposits exhibited a large density of nanoscale twins. The unique dual-scale grain and nano-twin structure found here caused apparent discrepancies in the grain size measured by XRD and by other …
-
The influence of microstructure on the mechanical properties of some refractory compounds
… carbide is linked to the presence of extended stacking faults. Suzuki hardening limited by bulk carbon diffusion is presented as the mechanism which distinguishes tantalum carbide from iv other carbides with the same structure. Softening is predicted to occur at temperatures near those observed …
-
Processing and deformation studies in high temperature ceramics
… the dissertation explores the role of intrinsic stacking faults in governing deformation mechanisms in HfN. The collective work reveals the link of structure in controlling either phase stability or mechanical deformation in these specific ceramics and their processing routes.
-
Development of a nanostructure thermal property measurement platform compatible with a transmission electron microscope
… such as the relationship between crystallinity, stacking faults, and dislocations to the sample's thermal transport properties. The work in this thesis details the development and fabrication of the measurement platform and further describes the development of a low-temperature measurement …
-
Influence of defects and impurities on solar cell performance
… defects such as grain boundaries, dislocations, stacking faults and impurity precipitates. Even though the effect of dislocations on mc-Si solar cell performance has been studied, a severe lack of understanding of the quantitative effects of dislocations on cell parameters still exists. Some …
-
Strength and ductility of Mg alloys from first-principles
… these cores based on solute interactions with stacking faults and strain. We show that the calculated misfit parameters are highly correlated so that only a few parameters are necessary to describe solute interactions in the dislocation cores. The geometric solute interaction models are …
-
Modeling microdefects formation in crystalline silicon : the roles of point defects and oxygen
… of void formation (aggregation of V's) and stacking faults (aggregation of I's). Second, the model of point defect and cluster dynamics has been extended to include oxygen, the most common impurity in silicon, and to model oxide precipitation, an important step in silicon wafer preparation …
-
Mechanics of Phase Transformation in NiTi Shape Memory Alloys at The Atomistic Scale
… as well as defects, such as dislocations and the stacking faults, are studied in the NiTi crystalline structure. In addition, the performance of NiTi under shock wave loading and vibrations, and their energy dissipation capabilities are examined using computational modeling, globally and locally. …
-
Advances in the modelling of in-situ powder diffraction data
… of various defects, like dislocations and stacking faults, are utilised in order to get the resulting diffraction profile. Two different systems with industrial application, CeO2 and Cu2ZnSnS4, which were produced using a sol-gel approach, were investigated.
-
Sintering behavior of Ag-Sn alloys prepared via cryogenic high-energy ball milling
… peak shifting attributed to the presence of stacking faults and dislocation loops. These alloys prove to sinter better and achieve higher densification than pure Ag. The 15at%Sn alloy achieves a density of 65% when compacted at 350◦C for 1hr under 7 MPa applied load, compared to 54% for pure …
-
Process-Structure-Property Relationship Study of Selective Laser Melting using Molecular Dynamics
… grains, nano-pores, twin boundaries, and stacking faults are observed in the final solidified nanostructure obtained after ten passes of the laser beam on three layers of Aluminum nano-powder particles. In the structure-property study, the mechanical deformation behavior of the complex …
Page 1 of 3