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Showing 1 to 20 of 108 for “"phase stability"”.
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Phase stability in ti/bcc multilayered thin films
… material adopting a different crystallographic phase. Often these phase transformations are serendipitously observed with the criteria for their stability difficult to ascertain. This work elucidates the underpinnings of phase stability behavior in the nanoscale regime by providing a systematic …
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Microstructural development, phase stability, and toughening in mullite matrix composites
… developed from an intermediate Al-Si spinel phase, while zirconia could develop by (1) nucleation, growth and subsequent transformation of cubic ZrO$\sb2$ particles from the amorphous matrix; (2) dissolution and reprecipitation from mullite grains; (3) decomposition from zircon (ZrSiO$\sb4$), …
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Total-energy models for phase-stability studies in multicomponent oxides
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997.
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Phase stability and formation in the Cu-Zn-Sn-S system
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-05-01
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Phase Stability In Cobalt-Based L12 Quaternary Intermetallics From Density Functional Theory
… additions (Mo, Ti, Ta, Hf, Fe, V) on the phase stability of L12 (γ’) intermetallics have been studied via first-principles. A 32 atom special-quasi-random structure was used to mimic the experimentally observed solid solution sublattice. Density of states distributions were generated in …
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Crystal Growth and Phase Stability of Metastable Indium Antimonide Bismide Thin Films
Made available in DSpace on 2014-12-14T16:00:41Z (GMT). No. of bitstreams: 1 8004315.pdf: 3022748 bytes, checksum: f6995803f1094ae3655edd827f8a6d7b (MD5) Previous issue date: 1979
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Experimental studies of magmatic differentiation and the effects of water on phase stability
… A major focus is the effect of water on the stability of mineral phases, and how this affects both the differentiation of magmas and the modification of the upper mantle by hydrous fluid release during subduction. Chapter 1 models the crystallization of the asteroid Vesta, which melted almost …
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Water in coesite and wadsleyite: quantification, incorporation mechanism and effect on the phase stability
… von Wassers auf die P-T-x Koordinaten des Ol-Wad Phasenüberganges. Im System MgO-SiO2-H2O wird durch den bevorzgten H-Einbau in Wad im Vergleich zum Ol die Ol-Wad Phasengrenze um 0.6 GPa zu niedrigeren Drücken verschoben. Im MgO-FeO-SiO2-H2O System verbreitet der H-Einbau die Felder, in denen …
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Processing and phase stability of metal carboxylate-derived barium-yttrium-copper oxide thin films
The processing and phase stability of Ba$\sb2$YCu$\sb3$O$\sb{\rm 7-x}$ High T$\sb{\rm c}$ thin films are seen to be critical aspects of the successful fabrication of this material. Metal neodecanoates of barium, yttrium, and copper were synthesized and mixed into a homogeneous, precipitate-free …
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Characterising Nanostructure and Understanding its Influence on Phase Stability and Performance in Halide Perovskites
… commercialized relate to device performance and phase stability: 1) In spite of their high performance, perovskites still exhibit a sizeable density of deep sub-gap non-radiative trap states, which create local variations in photoluminescence that fundamentally limit device performance. …
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Photovoltaic properties and size-pH phase stability of iron disulfide from density-functional theory
… effects of particle size and pH on the relative phase stability of pyrite and marcasite polymorphs are explored. The size effect is incorporated through volume scaling of Wulff shapes. The pH effect is modeled by generalized, charged surface energies as a result of ion adsorption from the aqueous …
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Compositional influences on the microstructures, phase stability, and mechanical properties of TiCr₂ laves phase alloys
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1996.
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Phase transformations in highly electrostrictive and magnetostrictive crystals: structural heterogeneity and history dependent phase stability
… crystals. In this thesis, I have to investigated phase transformations in these two systems under thermal and field (electric/magnetic) histories, using x-ray and neutron scattering techniques. In PMN-xPT crystals, x-ray and neutron diffractions were performed along the different crystallographic …
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Structure-property relationships and phase stability in the tin-modified lead zirconate titanate crystalline solution series
… will try to explain the influence of Sn on the phase stability and the transformational characteristics of high zirconium content lead zirconate titanate (PZT) ceramics. First, microstructural studies were done as a function of titanium content. An incommensurate phase was observed across much …
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Molecular Origins of Phase Stability in Phase-Change Nano-Emulsions for Thermal Energy Storage by NMR Spectroscopy
<p>Phase change materials (PCMs) are latent heat storage materials that can store or release thermal energy during phase transitions. Organic PCM nano-emulsions are formed by emulsifying oil in water in the presence of surfactants, enhancing thermal conductivity and pumpability. However, PCMs …
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Investigation of the mechanical properties and phase stability of Ti-transition metal alloys using first-principle calculations
… classes depending on the fraction of monoboride phase in the Ti-matrix, which makes them useful for broad applications such as aerospace and biomedical fields. Based on the design principle of searching for Ti-monoboride ceramic phases with higher Young’s modulus, higher Pugh’s ratio, and lower …
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Phase stability and the Portevin-Le Chatelier effect in Cr-Mn-Fe-Co-Ni High-Entropy Alloys
… It has been suggested that these solid solution phases could offer enhanced mechanical properties, due to fluctuations in their local atomic environments. However, at present, the thermodynamic stability of the solid solution phases which form in HEAs is poorly understood. This study aims to …
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Microstructural evolution and phase stability of Cu/Nb nanolaminates subjected to severe plastic deformation by high pressure torsion
… to investigate microstructural evolutions and phase stability as a function to strain, and to reach true steady states. The results show that the two dimensional layered microstructure was progressively replaced by a three-dimensional Cu-Nb nanocomposite. This structure remained stable with …
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An investigation into the phase stability of manganese oxide using quantum Monte Carlo and insights into materials prediction in the barium-ruthenium-sulfur phase space
… structure search in the barium-ruthenium-sulfur phase space using the evolutionary algorithm USPEX is presented. We identify find challenges to discovering new materials using an evolutionary algorithm as well as a potential new candidate structure, BaRu2S2 with space group 139.
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Design of Superelastic Secondary-Phase-Toughened Alloys
… the transformation product by designing a multi-phase alloy combining a superelastic phase with a stable elasto-plastic phase. In particular, nano- and micro-scale precipitates, lamellar structures, and bulk matrix morphologies of TiNi are investigated in combination with stable (V,Nb)-Ti matrix …
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