Physical Metallurgy of Beryllium and Its Alloys

Adhikari, Soumyakanti; Mukhopadhyay, Pradip

doi:10.1080/08827509408914114

Cited by 13 publications

(5 citation statements)

References 51 publications

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“…For demonstration, let's look at the high‐temperature phase, body‐centered cubic beryllium,

β

‐Be. Its electronic structure was calculated with ABINIT employing the JTH atomic datasets and the GGA‐PBE parametrization for exchange and correlation .…”

Section: Methodsmentioning

confidence: 99%

LOBSTER: A tool to extract chemical bonding from plane‐wave based DFT

et al. 2016

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The computer program LOBSTER (Local Orbital Basis Suite Towards Electronic‐Structure Reconstruction) enables chemical‐bonding analysis based on periodic plane‐wave (PAW) density‐functional theory (DFT) output and is applicable to a wide range of first‐principles simulations in solid‐state and materials chemistry. LOBSTER incorporates analytic projection routines described previously in this very journal [J. Comput. Chem. 2013, 34, 2557] and offers improved functionality. It calculates, among others, atom‐projected densities of states (pDOS), projected crystal orbital Hamilton population (pCOHP) curves, and the recently introduced bond‐weighted distribution function (BWDF). The software is offered free‐of‐charge for non‐commercial research. © 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.

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“…For demonstration, let's look at the high‐temperature phase, body‐centered cubic beryllium,

β

‐Be. Its electronic structure was calculated with ABINIT employing the JTH atomic datasets and the GGA‐PBE parametrization for exchange and correlation .…”

Section: Methodsmentioning

confidence: 99%

LOBSTER: A tool to extract chemical bonding from plane‐wave based DFT

et al. 2016

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“…The absence of any d-electrons in Be may result in a lower basal plane stacking fault energy and stabilize dissociation into Shockley partials on the basal plane. Adhikari & Mukhopadhyay [44] suggest that bonding within the basal plane of Be is metallic but along the c axis tends to have a more covalent character. Deformation temperature and strain rate have significant effects on CRSS values.…”

Section: Single-crystal Anisotropy (A) the Slip Systemsmentioning

confidence: 99%

On the mechanistic basis of deformation at the microscale in hexagonal close-packed metals

2015

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This is an overview of micromechanical deformation mechanisms in hexagonal close-packed metals. We start with an in-depth discussion of single-crystal behaviour concerning crystallographic slip, plastic anisotropy and deformation twinning. We move on to discuss some complexities involved in polycrystalline deformation and modelling approaches, focusing on rate effects in titanium alloys that are thought to play a significant role in dwell fatigue. We finish our review with a brief commentary on current understanding and state-of-the-art techniques, and outline some key areas where further study is recommended.

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“…[53] A more canonical example of this nodality phenomenon is solid beryllium being held together by hybridized 2p orbitals despite a single Be atom having only 2s valence electrons (2s orbitals have radial nodes but 2p do not). [54,55] In Figure 2, we show the Kohn-Sham orbitals of our DFT calculations for each valence and conduction band, plotted specifically at the  point such that all unit cells' orbitals are in-phase.…”

Section: Resultsmentioning

confidence: 99%

Why Yttrium Hexaboride Exhibits a Much Higher Superconducting Tc than Near-Identical Lanthanum Hexaboride

Lavroff,

Munarriz,

Dickerson

et al. 2023

Preprint

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Though YB6 and LaB6 share the same crystal structure, atomic valence electron configuration, and phonon modes, they exhibit drastically different phonon-mediated superconductivity. YB6 superconducts below 8.4 K, giving it the second-highest critical temperature of known borides. LaB6 does not superconduct until near-absolute zero temperatures, however. Though previous studies have quantified the canonical superconductivity descriptors of YB6’s greater Fermi-level (Ef) density of states and higher electron-phonon coupling (EPC), the root of this difference has not been assessed with full detail of the electronic structure. Through chemical bonding, we determine low-lying, unoccupied 4f atomic orbitals in lanthanum to be the key difference between these superconductors. These orbitals, which are not accessible in YB6, hybridize with pi B-B bonds and bring this pi-system lower in energy than the sigma B-B bonds otherwise at Ef. This inversion of bands is crucial: the phonon modes we show responsible for superconductivity cause the sigma-orbitals of YB6 to change drastically in overlap, but couple weakly to the pi-orbitals of LaB6. These phonons in YB6 even access an electronic-state crossing, indicating strong EPC. No such crossing in LaB6 is observed. Finally, a supercell (the M k-point) is shown to undergo a Peierls-like effect in YB6, introducing additional EPC.

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Physical Metallurgy of Beryllium and Its Alloys

Cited by 13 publications

References 51 publications

LOBSTER: A tool to extract chemical bonding from plane‐wave based DFT

LOBSTER: A tool to extract chemical bonding from plane‐wave based DFT

On the mechanistic basis of deformation at the microscale in hexagonal close-packed metals

Why Yttrium Hexaboride Exhibits a Much Higher Superconducting Tc than Near-Identical Lanthanum Hexaboride

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