Effects of vacancies on the mechanical properties of zirconium: An ab initio investigation

Zhu, Xueyan; Gao, Xingyu; Song, Haifeng; Han, Guomin; Lin, De-Ye

doi:10.1016/j.matdes.2017.01.060

Cited by 33 publications

(9 citation statements)

References 55 publications

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“…5(a) , the BSBS power gain is shown as a function of the defect-induced stiffness change, Δ c , assuming air cover, H = 300 nm, W = 236 nm, λ p = 450 nm and Q factor = 3000. Our investigations indicate that with the increase of Δ c from 0 to 30 GPa, the bulk modulus (defined as in 31 ) decreases monotonically, inducing the reduction of Al x Ga 1−x N resistance to uniform compression. At the same time, shear modulus, and Young’s modulus (defined as in 31 ) increase monotonically, while the Poisson’s ratio decreases.…”

Section: Resultsmentioning

confidence: 66%

“…Our investigations indicate that with the increase of Δ c from 0 to 30 GPa, the bulk modulus (defined as in 31 ) decreases monotonically, inducing the reduction of Al x Ga 1−x N resistance to uniform compression. At the same time, shear modulus, and Young’s modulus (defined as in 31 ) increase monotonically, while the Poisson’s ratio decreases. This means that the presence of defects could enhance the resistance to shear and uniaxial stresses.…”

Section: Resultsmentioning

confidence: 66%

“…However, it has been rarely studied how the point defect changes the mechanical properties. Only recently it was found that defects such as uniformly distributed vacancies or vacancy clusters induce, in hexagonal systems, an increase in c ′ 11 , c ′ 33 , and c ′ 44 and a decrease of c ′ 12 , and c ′ 13 31 . Due to the lack of experimental data for the alloy Al x Ga 1−x N, we guess, as hypothesis of the worst case, that all five independent stiffness tensor elements suffer from the same change, ±Δ c .…”

Section: Resultsmentioning

confidence: 99%

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Stimulated Brillouin Scattering in an AlGaN Photonics Platform Operating in the Visible Spectral Range

Leonardis

Soref

Soltani

et al. 2018

Sci Rep

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We present Stimulated Brillouin Scattering (SBS) process in AlGaN integrated photonic waveguides. The wide bandgap of this III-Nitride material platform allows operating at visible wavelengths enabling large Stokes shifts. For this study, we employ a multiphysics approach that includes electric-photoelastic, magnetic-photoelastic, material interface displacement effects, and for optimal waveguide dimensions to find the Brillouin-active acoustic modes involved in the SBS process. The SBS power gain and the Stokes frequency shift are investigated for both backward and forward scattering processes, and it is shown that stokes shift larger than 50 GHz with high gain are achievable. Moreover, a parametric analysis is presented in order to demonstrate the possibility of realizing Brillouin lasers operating at blue wavelengths.

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Section: Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 99%

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Stimulated Brillouin Scattering in an AlGaN Photonics Platform Operating in the Visible Spectral Range

Leonardis

Soref

Soltani

et al. 2018

Sci Rep

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“…The RBS measurements were conducted using incident angle α =75°, exit angle β = 65°, scattering angle θ = 170° and 4 He +2 energy 3.045 MeV at Joint Institute of Nuclear Research. Although RBS discriminates strongly against light elements in a heavy substrate, such as oxygen in the metal alloys lattice, the use of the resonant reaction 16 O(α, α) 16 O at 3.04 MeV is very beneficial, as its cross section is nearly 23 times as that of the Rutherford cross section [25].…”

Section: Rbs Techniquementioning

confidence: 99%

“…It is commonly known that structural defects change mechanical properties of a material. For example, ab initio calculations performed by Zhu et al [16] for α-Zr showed that increasing vacancy concentration up to 3% decreases both the bulk modulus and ductility, but increases the shear and Young's moduli and hardness. It was also pointed out that vacancy clusterization strengthens these changes.…”

Section: Introductionmentioning

confidence: 99%

Surface and Subsurface Defects Studies of Dental Alloys Exposed to Sandblasting

Siemek

Kulik

Есеев

et al. 2019

Acta Metall. Sin. (Engl. Lett.)

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The defects created in commercial dental alloys during blasting with alumina particles propelled in compressed air under pressure 0.1 and 0.4 MPa have been studied using positron annihilation spectroscopy, scanning electron microscopy and X-ray diffraction. It was observed that higher pressure causes the increase in roughness and damaged zone range. The type of defects was determined as vacancies on dislocations. The defect concentration decreases with the depth and depends on alloys' type and applied pressure. The Rutherford backscattering spectroscopy and variable energy positron beam studies indicate shallow alumina deposition in material and show that small pressure of 0.1 MPa is not enough to remove metal surface oxides completely in 60 s in all studied dental alloys.

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Influence of Local Lattice Distortion on Elastic Properties of Hexagonal Close‐Packed TiZrHf and TiZrHfSc Refractory Alloys

Meng

Duan

Chen

et al. 2021

Physica Status Solidi (b)

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The unique mechanical properties and local lattice distortion (LLD) for hexagonal close‐packed (HCP) multiple principal element alloys (MPEAs) are very rarely studied so far. Employing density functional theory calculation based on special quasirandom structure, this work studies the influences of LLD on elastic properties for both novel hexagonal TiZrHf(Sc) MPEAs. Compared to the pristine structures, the lattice stability of distorted random structures is improved evidently. Moreover, LLD obviously lessens the shear elastic properties, which may be an ubiquitous phenomenon irrespective of the lattice types of MPEAs. These results also uncover the apparent improvement in malleable behavior and shear anisotropy for HCP MPEAs. So, the influence of LLD on elastic properties for HCP MPEAs is profound. The degree of LLD is further studied via the standard deviation of near‐neighbor (NN) and next NN bond length distributions as an effective indicator of LLD. More significant distortion uncovered in TiZrHf alloy corresponds consistently to the stronger effects of LLD in TiZrHf alloy. Bader's charge and charge density distribution also demonstrate the underlying impact on LLD for both HCP MPEAs, so electronic nature is a significant factor for LLD. The present study provides guideline for designing mechanical properties of TiZrHf‐based HCP MPEAs engineering materials.

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Effects of vacancies on the mechanical properties of zirconium: An ab initio investigation

Cited by 33 publications

References 55 publications

Stimulated Brillouin Scattering in an AlGaN Photonics Platform Operating in the Visible Spectral Range

Stimulated Brillouin Scattering in an AlGaN Photonics Platform Operating in the Visible Spectral Range

Surface and Subsurface Defects Studies of Dental Alloys Exposed to Sandblasting

Influence of Local Lattice Distortion on Elastic Properties of Hexagonal Close‐Packed TiZrHf and TiZrHfSc Refractory Alloys

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