Dislocation nodes in boron carbide, with special reference to non-stoichiometry

Ashbee, K. H. G.; DuBose, C.K.H.

doi:10.1016/0001-6160(72)90186-1

Cited by 18 publications

(9 citation statements)

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“…As a control rod material, the defect structure in neutron irradiated B 4 C was investigated by Ashbee [3,4], Jostsons [5,6], Hollenberg [7] and Donomae [8] et al He + implantation of B 4 C has been performed by Stoto [9] and Maruyama [10]. Irradiation effects and helium bubble formation in aluminum after high energy proton irradiation were reported by Singh and Victoria [11,12].…”

Section: Neutronsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The gamma and neutron doses received in the MMC depend on a number of factors including fuel burnup, storage time, and the self-shielding of the fuel assemblies. In spent fuel fool storage, the neutron flux can be as high as 2.6 Â 10 5 neutron/cm 2 s and the gamma dose rate is in the range of 0.1-10 kGy/h [1,2], corresponding to several thousand appm of transmuted helium build up and 1-2 dpa (displacement per atom) of damage during the estimated storage period of 60 years in spent fuel pool storage and about 200 years in the dry storage casks.As a control rod material, the defect structure in neutron irradiated B 4 C was investigated by Ashbee [3,4], Jostsons [5,6], Hollenberg [7] and Donomae [8] et al He + implantation of B 4 C has been performed by Stoto [9] and Maruyama [10]. Irradiation effects and helium bubble formation in aluminum after high energy proton irradiation were reported by Singh and Victoria [11,12].…”

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Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

et al. 2015

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a b s t r a c tHelium behavior in Al/B 4 C metal matrix composite with two different sets of ion irradiation conditions has been investigated by transmission electron microscopy. Helium bubbles in Al were found to be much larger than those in B 4 C after a helium fluence of 1.5 Â 10 17 ions/cm 2 at the room temperature. Also, bubbles at grain boundaries and their vicinity in aluminum are faceted. With additional proton irradiation, a bubble denuded zone along the aluminum grain boundary appears. The results are discussed in terms of the energetics of the material system.Ó 2015 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.Al/B 4 C metal matrix composite (MMC) is an important neutron absorbing material used in both wet storage pools and dry storage casks of spent nuclear fuel for preventing criticality. Al/B 4 C MMC can effectively absorb fast and thermal neutrons, because of the high neutron absorption cross-section of 10 B through the 10 B(n, a) 7 Li transmutation reaction for a wide energy range of neutrons.The damage produced by elastic collisions between neutrons and other energetic particles generated by transmutation reactions with the target atoms along with the build-up of helium concentration in the MMC may lead to the precipitation of helium bubbles. The gamma and neutron doses received in the MMC depend on a number of factors including fuel burnup, storage time, and the self-shielding of the fuel assemblies. In spent fuel fool storage, the neutron flux can be as high as 2.6 Â 10 5 neutron/cm 2 s and the gamma dose rate is in the range of 0.1-10 kGy/h [1,2], corresponding to several thousand appm of transmuted helium build up and 1-2 dpa (displacement per atom) of damage during the estimated storage period of 60 years in spent fuel pool storage and about 200 years in the dry storage casks.As a control rod material, the defect structure in neutron irradiated B 4 C was investigated by Ashbee [3,4], Jostsons [5,6], Hollenberg [7] and Donomae [8] et al. He + implantation of B 4 C has been performed by Stoto [9] and Maruyama [10]. Irradiation effects and helium bubble formation in aluminum after high energy proton irradiation were reported by Singh and Victoria [11,12]. The precipitation of helium causes not only changes in microstructure but degradation in the physical, chemical and mechanical properties of Al/B 4 C MMC, such as, reduced thermal conductivity, decreased corrosion resistance and volume swelling. The property change in Al/B 4 C MMC affects the long-term performance of the MMC in its working environment. In fact, irradiation induced microcracking in B 4 C that leads to increased boron release was reported by Copeland [13] and Stoto [14].This paper focuses on helium bubble formation upon helium implantation and bubble evolution during additional proton irradiation in the Al/B 4 C MMC. Ion irradiations were conducted to simulate the effects of radiation and helium build-up in Al/B 4 C MMC as neutron absorbers in wet storage pool and dry storage casks. Angular shape B 4 C particles w...

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Section: Neutronsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

et al. 2015

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“…If the radiation interaction occurs in a semiconductor, for each neutron captured, ~1.5 x 10 6 electronhole pairs are produced as the energetic 7 Li and 4 He ions pass through the material [1,2]. This ionization generates a current that can be detected directly without further amplification.…”

Section: Introductionmentioning

confidence: 99%

“…The study of such imperfections or defects is important for understanding the influence of imperfections on crystal-growth processes, and conversely, such feedback can be used to optimize the process to produce higher quality crystals [4]. Hence, it is essential for process engineers and crystal growers to characterize and identify the density, distribution, and nature of defects present in crystals.…”

Section: Introductionmentioning

confidence: 99%

Defect-Selective Etching of Icosahedral Boron Arsenide (B₁₂As₂) Crystals in Molten Potassium Hydroxide

et al. 2011

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The present work reports on the defect-selective etching (DSE) for estimating dislocation densities in icosahedral boron arsenide (B 12 As 2 ) crystals using molten potassium hydroxide (KOH). DSE takes advantage of the greater reactivity of high-energy sites surrounding a dislocation, compared to the surrounding dislocation-free regions. The etch pits per area are indicative of the defect densities in the crystals, as confirmed by x-ray topography (XRT). Etch pit densities were determined for icosahedral boron arsenide crystals produced from a molten nickel flux as a function of etch time (1-5 minutes) and temperature (400-700°C). The etch pits were predominately triangle shaped, and ranged in size from 5-25μm. The average etch pit density of the triangle and oval etch-pits was on the order of 5x10 7 cm -2 and 3x10 6 cm -2 (respectively), for crystals that were etched for two minutes at 550°C.

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Institutional and technical history of requirements‐based strategic armor ceramics basic research leading up to the multiscale material by design materials in extreme dynamic environments (MEDE) program. Part II: Dynamic effects on the physics and mechanisms of advanced ceramics such as boron carbide

McCauley

Ramesh

2023

Int J Ceramic Engine & Sci

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This paper follows a historical background on requirements-based strategic armor research, leading to the materials in extreme dynamic environments program presented in Part I, now focusing on the developed technical aspects and state-of-the-art. It starts with some background on dynamic testing techniques and a structural ceramics review. Then, selected armor ceramics research results and relevant single-grain anisotropic crystal physics, microstructure, and defect mechanics mechanisms: Including pivotal armor ceramics research results prior to the adoption of the strategic research objective (SRO). Next, multiscale characteristics, crystal physics, planar features, anisotropy, and relevant mechanisms will be described. The historic progression/evolution of multiscale lightweight armor ceramics research results will be summarized, including multiscale dynamic deformation and damage characteristics. The focus of the following sections will be on the role of defects, quasi-plasticity, and anisotropic crystal physics properties, including preexisting single grain synthesis and process-induced planar features (aka twins) and planar deformation features (PDF); for example, nano-amorphization in boron carbide. A new model for boron carbide processing planar features will be discussed. A schematic diagram illustrating the hypothetical formation of PDFs in a dynamic event is also presented. An expended canonical equation is introduced, suggesting possible strategies for boron carbide research using the canonical figures of merit approach. Finally, we highlight the efficacy of the materials by design process and approach in a multiscaleThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Dislocation nodes in boron carbide, with special reference to non-stoichiometry

Cited by 18 publications

References 4 publications

Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

Defect-Selective Etching of Icosahedral Boron Arsenide (B₁₂As₂) Crystals in Molten Potassium Hydroxide

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Dislocation nodes in boron carbide, with special reference to non-stoichiometry

Cited by 18 publications

References 4 publications

Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

Helium bubble evolution in ion irradiated Al/B4C metal metrix composite

Defect-Selective Etching of Icosahedral Boron Arsenide (B12As2) Crystals in Molten Potassium Hydroxide

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Defect-Selective Etching of Icosahedral Boron Arsenide (B₁₂As₂) Crystals in Molten Potassium Hydroxide