The ideal strength of tungsten

Roundy, David; Krenn, C. R.; Cohen, Marvin L.; Morris, J. W.

doi:10.1080/01418610108216634

Cited by 244 publications

(158 citation statements)

References 28 publications

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“…Since, owing to the symmetry, the bcc and fcc structures correspond to the minimum and maximum of the energy, respectively, the inflection point between the two structures on the path determines the ideal tensile strength. Previous DFT calculations of Šob et al 92 and Roundy et al 97 identified the ͗001͘ axis as the weak direction in tension and the ͕001͖ planes as the cleavage planes. Calculations employing BOP's follow closely the DFT ones, indicating that both the ideal tensile stress and strain will be in good agreement with the ab initio values.…”

Section: B Deformation Pathsmentioning

confidence: 99%

Bond-order potential for simulations of extended defects in tungsten

et al. 2007

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We present a bond-order potential (BOP) for the bcc transition metal tungsten. The bond-order potentials are a real-space semiempirical scheme for the description of interatomic interactions based on the tight-binding approximation. In the hierarchy of atomic-scale-modeling methods the BOPs thus provide a direct bridge between electronic-structure and atomistic techniques. Two variants of the BOP were constructed and extensively tested against accurate first-principles methods in order to assess the potentials' reliability and applicability. A comparison of the BOP with a central-force potential is used to demonstrate that a correct description of directional mixed covalent and metallic bonds is crucial for a successful and fully transferable model. The potentials are applied in studies of low-index surfaces, symmetrical tilt grain boundaries, and dislocations. We present a bond-order potential ͑BOP͒ for the bcc transition metal tungsten. The bond-order potentials are a real-space semiempirical scheme for the description of interatomic interactions based on the tight-binding approximation. In the hierarchy of atomic-scale-modeling methods the BOPs thus provide a direct bridge between electronic-structure and atomistic techniques. Two variants of the BOP were constructed and extensively tested against accurate first-principles methods in order to assess the potentials' reliability and applicability. A comparison of the BOP with a central-force potential is used to demonstrate that a correct description of directional mixed covalent and metallic bonds is crucial for a successful and fully transferable model. The potentials are applied in studies of low-index surfaces, symmetrical tilt grain boundaries, and dislocations.

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Section: B Deformation Pathsmentioning

confidence: 99%

Bond-order potential for simulations of extended defects in tungsten

et al. 2007

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“…In bcc Mo, W, and Fe, ͕110͖͗111͘, ͕211͖͗111͘, and ͕321͖͗111͘ affine shears have the lowest and almost degenerate w shear values suggesting possible pencil glide. 18 In hcp metals, the minimizer of w shear correctly predicts the preference of basal versus prism slip, with the exception of Ti. Such abnormality could be due to DFT error; but even when such slip system ranking error occurs, the difference in w shear value is so small that it will not impact the Eq.…”

Section: Theorymentioning

confidence: 99%

Toughness scale from first principles

Ogata

2009

Journal of Applied Physics

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We correlate the experimentally measured fracture toughness of 24 metals and ceramics to their quantum mechanically calculated brittleness parameter. The brittleness parameter is defined as the ratio of the elastic energy density needed to spontaneously break bonds in shear versus in tension, and is a primitive-cell property. Under 300 GPa hydrostatic pressure, the model predicts that diamond has smaller brittleness than molybdenum at zero pressure, and thus should deform plastically without cracking at room temperature. Disciplines Engineering | Materials Science and Engineering CommentsSuggested Citation: Ogata, S. and J. Li. (2009) We correlate the experimentally measured fracture toughness of 24 metals and ceramics to their quantum mechanically calculated brittleness parameter. The brittleness parameter is defined as the ratio of the elastic energy density needed to spontaneously break bonds in shear versus in tension, and is a primitive-cell property. Under 300 GPa hydrostatic pressure, the model predicts that diamond has smaller brittleness than molybdenum at zero pressure, and thus should deform plastically without cracking at room temperature.

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“…21,22 The eigenvalues of the symmetrized Wallace tensor, 13,23 λ ijkl , govern the elastic stability of a material following…”

Section: Theorymentioning

confidence: 99%

Dislocations near elastic instability in high-pressure body-centered-cubic magnesium

et al. 2017

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At high pressure, Mg is expected to transform to the body-centered cubic (BCC) phase. We use density functional theory to explore the structure of 111 -type dislocation cores in BCC Mg as a function of pressure. As the pressure is reduced from the region of absolute stability for the BCC phase, the dislocation cores spread. When dislocation cores overlap the displacements of columns of atoms resemble the nanodisturbances observed in TiNb alloys known as Gum Metal. As the pressure is lowered further, these regions transform into the hexagonal close-packed (HCP) phase.The ideal tensile strength of BCC Mg is also computed as a function of pressure. Despite its low shear modulus, BCC Mg is predicted to be intrinsically brittle at absolute zero.

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The ideal strength of tungsten

Cited by 244 publications

References 28 publications

Bond-order potential for simulations of extended defects in tungsten

Bond-order potential for simulations of extended defects in tungsten

Toughness scale from first principles

Dislocations near elastic instability in high-pressure body-centered-cubic magnesium

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