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Weathering of Granitic Muscovite to Kaolinite and Halloysite and of Plagioclase-Derived Kaolinite to Halloysite
- Ian D. M. Robertson, Richard A. Eggleton
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- Journal:
- Clays and Clay Minerals / Volume 39 / Issue 2 / April 1991
- Published online by Cambridge University Press:
- 02 April 2024, pp. 113-126
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Weathered perthite and mixed muscovite-kaolinite from a kaolinitic granite at Trial Hill in east Queensland and kaolinized sericitic alteration from a granite from the Ardlethan Tin Mine of New South Wales were examined by optical, scanning electron (SEM), and transmission electron microscopy (TEM) to determine the alteration process of muscovite to kaolinite and kaolinite to halloysite (7Å). Muscovite was found intimately interleaved with kaolinite in a variety of proportions on a sub-micrometer scale. The contact was generally parallel to the (001) layers of both minerals, and the thickness of the contact layer alternated between 10 and 7 Å over short distances. Where the kaolinite to muscovite contact was at an acute angle to the muscovite layers, a small angle existed between the layering of the two phases, consistent with a topotactic alteration of muscovite to kaolinite. One tetrahedral sheet in the muscovite appeared to have been removed over 50–100 Å, converting a 10-Å layer to a 7-Å layer. The mica near the contact with kaolinite was easily damaged in the electron beam and showed Al loss during analytical transmission electron microscopy; thus, H3O+ probably substituted for K+ in this transitional phase.
An SEM examination of completely weathered plagioclase showed kaolinite plates having attached, parallel, polygonal rods of halloysite (7Å), which had planar sides and a central void, partly fused with the surfaces of the kaolinite crystals. TEM study showed that the kaolinite altered to halloysite, and that, where the kaolinite was partly altered to halloysite, a series of sharp kinks were present in the kaolinite plate in which alteration had occurred. These kinks were interspersed with linear kaolinite relics, 0.1–0.2 μm long, which appear to have provided local rigidity to the clay packet. Apparently, the altered clay first curled into loosely wound spirals, which ranged in cross-section from triangles to irregular octagons, with pentagons and hexagons being most common. The tendency to pentagons and hexagons compares well with a statistical study of the angles, which were most commonly grouped around 120°. As alteration of the kaolinite relics progressed, the linear parts of the spiral lost their rigidity and became circular or oval shaped. The long axis of the halloysite spirals was parallel to the X axis of the kaolinite. Halloysite spirals formed most readily if they had space to curl; if space was not available, the halloysite formed sheaves. Rare, thin layers of muscovite were present projecting through kaolinite into halloysite. Where muscovite relics reached open spaces, the 10-Å structure expanded to 14 Å.
Influence of chemical disorder on energy dissipation and defect evolution in advanced alloys
- Yanwen Zhang, Ke Jin, Haizhou Xue, Chenyang Lu, Raina J. Olsen, Laurent K. Beland, Mohammad W. Ullah, Shijun Zhao, Hongbin Bei, Dilpuneet S. Aidhy, German D. Samolyuk, Lumin Wang, Magdalena Caro, Alfredo Caro, G. Malcolm Stocks, Ben C. Larson, Ian M. Robertson, Alfredo A. Correa, William J. Weber
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- Journal:
- Journal of Materials Research / Volume 31 / Issue 16 / 29 August 2016
- Published online by Cambridge University Press:
- 26 August 2016, pp. 2363-2375
- Print publication:
- 29 August 2016
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Historically, alloy development with better radiation performance has been focused on traditional alloys with one or two principal element(s) and minor alloying elements, where enhanced radiation resistance depends on microstructural or nanoscale features to mitigate displacement damage. In sharp contrast to traditional alloys, recent advances of single-phase concentrated solid solution alloys (SP-CSAs) have opened up new frontiers in materials research. In these alloys, a random arrangement of multiple elemental species on a crystalline lattice results in disordered local chemical environments and unique site-to-site lattice distortions. Based on closely integrated computational and experimental studies using a novel set of SP-CSAs in a face-centered cubic structure, we have explicitly demonstrated that increasing chemical disorder can lead to a substantial reduction in electron mean free paths, as well as electrical and thermal conductivity, which results in slower heat dissipation in SP-CSAs. The chemical disorder also has a significant impact on defect evolution under ion irradiation. Considerable improvement in radiation resistance is observed with increasing chemical disorder at electronic and atomic levels. The insights into defect dynamics may provide a basis for understanding elemental effects on evolution of radiation damage in irradiated materials and may inspire new design principles of radiation-tolerant structural alloys for advanced energy systems.
Towards an integrated materials characterization toolbox
- Ian M. Robertson, Christopher A. Schuh, John S. Vetrano, Nigel D. Browning, David P. Field, Dorte Juul Jensen, Michael K. Miller, Ian Baker, David C. Dunand, Rafal Dunin-Borkowski, Bernd Kabius, Tom Kelly, Sergio Lozano-Perez, Amit Misra, Gregory S. Rohrer, Anthony D. Rollett, Mitra L. Taheri, Greg B. Thompson, Michael Uchic, Xun-Li Wang, Gary Was
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- Journal:
- Journal of Materials Research / Volume 26 / Issue 11 / 14 June 2011
- Published online by Cambridge University Press:
- 07 June 2011, pp. 1341-1383
- Print publication:
- 14 June 2011
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The material characterization toolbox has recently experienced a number of parallel revolutionary advances, foreshadowing a time in the near future when material scientists can quantify material structure evolution across spatial and temporal space simultaneously. This will provide insight to reaction dynamics in four-dimensions, spanning multiple orders of magnitude in both temporal and spatial space. This study presents the authors’ viewpoint on the material characterization field, reviewing its recent past, evaluating its present capabilities, and proposing directions for its future development. Electron microscopy; atom probe tomography; x-ray, neutron and electron tomography; serial sectioning tomography; and diffraction-based analysis methods are reviewed, and opportunities for their future development are highlighted. Advances in surface probe microscopy have been reviewed recently and, therefore, are not included [D.A. Bonnell et al.: Rev. Modern Phys. in Review]. In this study particular attention is paid to studies that have pioneered the synergetic use of multiple techniques to provide complementary views of a single structure or process; several of these studies represent the state-of-the-art in characterization and suggest a trajectory for the continued development of the field. Based on this review, a set of grand challenges for characterization science is identified, including suggestions for instrumentation advances, scientific problems in microstructure analysis, and complex structure evolution problems involving material damage. The future of microstructural characterization is proposed to be one not only where individual techniques are pushed to their limits, but where the community devises strategies of technique synergy to address complex multiscale problems in materials science and engineering.
Contributors
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- By Claude Alain, Amy F. T. Arnsten, Lars Bäckman, Malcolm A. Binns, Sandra E. Black, S. Thomas Carmichael, Keith D. Cicerone, Maurizio Corbetta, Bruce Crosson, Jeffrey L. Cummings, Deirdre R. Dawson, Michael deRiesthal, Roger A. Dixon, Laura Eggermont, Kirk I. Erickson, Anthony Feinstein, Susan M. Fitzpatrick, Fu Qiang Gao, Douglas D. Garrett, Omar Ghaffar, Robbin Gibb, Elizabeth L. Glisky, Martha L. Glisky, Leslie J. Gonzalez Rothi, Cheryl L. Grady, Carol Greenwood, Gerri Hanten, Richard G. Hunter, Masud Husain, Narinder Kapur, Bryan Kolb, Arthur F. Kramer, Susan A. Leon, Harvey S. Levin, Brian Levine, Nadina Lincoln, Thomas W. McAllister, Edward McAuley, Bruce S. McEwen, David M. Morris, Stephen E. Nadeau, Roshan das Nair, Matthew Parrott, Jennie Ponsford, George P. Prigatano, Joel Ramirez, John M. Ringman, Ian H. Robertson, Amy D. Rodriguez, John C. Rosenbek, Bernhard Ross, Erik Scherder, Victoria Singh-Curry, Trudi Stickland, Donald T. Stuss, Edward Taub, Gary R. Turner, Harry V. Vinters, Samuel Weiss, John Whyte, Barbara A. Wilson, Gordon Winocur, J. Martin Wojtowicz
- Edited by Donald T. Stuss, University of Toronto, Gordon Winocur, University of Toronto, Ian H. Robertson, Trinity College, Dublin
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- Book:
- Cognitive Neurorehabilitation
- Published online:
- 05 September 2015
- Print publication:
- 11 September 2008, pp ix-xiv
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