Structural instability of uniaxially compressed α-quartz

Subramanian, Sundararaman; Yip, Sidney

doi:10.1016/s0927-0256(01)00222-1

Cited by 7 publications

(7 citation statements)

References 31 publications

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“…Since this is a well-known transformation when quartz is heated, we have demonstrated the equivalence between thermal and mechanical strains [4]. Under hydrostatic compression we obtain a transition to amorphous at 20 GPa [5] which is close to the experimental value.…”

Section: Theoretical Strength Of Fi -Sic and A -Sio^supporting

confidence: 85%

High Temperature Strengths and Deformation of Ceramics

Yip¹

2003

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Public reporting burden for this collection of infomiatian is estimated to average 1 hour per response, including the time for reviewing instrucjions ABSTRACT (Maximum 200 words)This project developed a computational modeling capability to smdy the theoretical strengths and deformation mechanisms o structural ceramics for high temperature applications. The approach adopted was molecular dynamics simulation based on appropriate interatomic potential models. The studies focused on ZrC that has excellent high-temperature properties, and to a lesser extent on SiC and Si02. Strain-to-failure sunulations were performed to observe the details of the structural instability and subsequent microstructural evolution. Besides single crystals, deformations in the amorphous and nanocrystalline phases were also investigated. In parallel elastic stiffness and other mechanical properties were calculated to correlate with and interpret the simulation resuhs. The research performed in this project has demonstrated the feasibility ol modeling the intrinsic mechanical and thermal properties of ceramics. The results obtained contribute to a database of structure-property correlation that provides a foundation for further computational studies of ceramics for high temperature applications. It appears that modeling and simulation at the atomistic level have reached a level of physical robustness that one can begin to develop detailed understanding of certain ceramics under conditions of practical interest.

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Section: Theoretical Strength Of Fi -Sic and A -Sio^supporting

confidence: 85%

High Temperature Strengths and Deformation of Ceramics

Yip¹

2003

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“…In our simulations, as with many of these experiments, a confining pressure (1.55 GPa) and a high temperature (1073 K) were chosen to probe the plastic deformation of quartz crystals without incurring any faulting. Some of the results have been discussed previously [67,68]. We summarize the main points and add some previously unpublished results.…”

Section: Stress-controlled Deformationmentioning

confidence: 61%

“…In simulation, BKS α-quartz becomes unstable around 20 GPa, when pressureinduced amorphization occurs either directly [68,74] or through intermediate crystalline phases [73,77]. Campañá et al [9] showed that amorphization can be avoided up to at least 50 GPa.…”

Section: Strain-controlled Deformationmentioning

confidence: 99%

Atomic Scale Chemo-mechanics of Silica: Nano-rod Deformation and Water Reaction

Silva

Liao

et al. 2006

J Computer-Aided Mater Des

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The notion of bond rupture as the initiation event leading to mechanical failure in a material system is well known. Less recognized but no less valid is that bond strain also fundamentally affects the chemical reactivity of the atoms involved in the bonding. This dual role of bond strain is clearly brought out in the present simulations. Stress-strain response of dry silica to the point of structural instability is studied using a classical inter-atomic potential model, whereas transition-state pathway sampling of water-silica reaction is performed using molecular orbital theory. Although not as accurate as possible from the standpoint of existing methods of simulation, the results nevertheless illustrate the physical insights into chemo-mechanical processes one can extract through multi-scale modeling and simulation.

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“…The ideal ͑theoretical͒ strength, which is, in general, defined for a perfect crystal subject to a uniform deformation as the stress at which an unstable deformation takes place, was originally discussed using simple interatomic potential. [9][10][11] Since the ideal strength, which is the highest attainable stress of the material, is a fundamental mechanical property, a lot of studies for various crystals have been performed, employing not only empirical potential [12][13][14][15][16][17][18][19][20][21] but also first principles ͑ab initio͒ methodology. [22][23][24][25][26][27][28] Through these efforts the ideal strength of perfect crystals has been well investigated.…”

Section: Introductionmentioning

confidence: 99%

Ab initiostudy of the surface properties and ideal strength of (100) silicon thin films

et al. 2005

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Studying the ideal strength of nanostructured materials is important for understanding of their mechanical properties. We have performed ab initio modeling of nanoscale Si films with ͑100͒ surfaces and computed the surface energy and surface stress as well as the ideal tensile strength of the structure. The strength of the thin film is not significantly decreased down to a thickness of less than 1 nm. Surprisingly, there is also no considerable effect of the surface reconstruction. This suggests that the lower stresses found for surface crack nucleation in an experiment are due to substantial flaws and not an intrinsic effect of the ideal surface. The band gap energy of the thin film is lower than that of the bulk, but a band gap remains up to high strain in the thin film.

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Structural instability of uniaxially compressed α-quartz

Cited by 7 publications

References 31 publications

High Temperature Strengths and Deformation of Ceramics

High Temperature Strengths and Deformation of Ceramics

Atomic Scale Chemo-mechanics of Silica: Nano-rod Deformation and Water Reaction

Ab initiostudy of the surface properties and ideal strength of (100) silicon thin films

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