Journal ArticleDOI
A quantitative demonstration of the grain boundary diffusion mechanism for the oxidation of metals
TLDR
In this article, the authors report measurements of the oxide scale thickness and oxide grain size as a function of time during the oxidation of high-purity nickel in the temperature range 500-800°C.Abstract:
Below 1000°C the oxidation of nickel cannot be controlled by the diffusion of ions through the bulk crystal lattice of the pure oxide, because the measured oxidation rates are several orders of magnitude faster than would be predicted on this basis. Short-circuit diffusion through oxide grain boundaries or dislocations has usually been held responsible, but there has hitherto been no proper quantitative confirmation of this mechanism. We report measurements of the oxide scale thickness and oxide grain size as a function of time during the oxidation of high-purity nickel in the temperature range 500–800°C. All the oxidation experiments were carried out in pure oxygen at a pressure of one atmosphere. The measured parabolic oxidation rate constants have been compared with those calculated from grain boundary diffusion data obtained in our previous work, using a grain boundary diffusion model for the oxidation process. The quantitative agreement between measured and calculated oxidation rates shows c...read more
Citations
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Trends in the elastic response of binary early transition metal nitrides
TL;DR: In this article, the elastic response of nine binary early transition metal nitrides (ScN, TiN, VN, YN, ZrN, NbN, LaN, HfN, and TaN) and AlN were studied.
Journal ArticleDOI
Elastic and plastic properties of as-cast equimolar TiHfZrTaNb high-entropy alloy
Guy Dirras,Lola Lilensten,Ph. Djemia,Mathilde Laurent-Brocq,David Tingaud,Jean-Philippe Couzinié,Loïc Perrière,Thierry Chauveau,Ivan Guillot +8 more
TL;DR: In this article, the elastic properties of as-cast TiHfZrTaNb high entropy alloy were investigated by ultrasound measurements, yielding G=C44=28 GPa and C11=172 GPa effective isotropic elastic constants, allowing computation of the Young's modulus E, the bulk modulus B and Poisson ratio ν of about 78.5 GPa, 134.6GPa and 0.402.
Journal ArticleDOI
Anisotropic elastic properties of the Ca–Pb compounds
TL;DR: In this article, the structural and elastic properties of Ca-Pb intermetallic compounds were investigated by using the first-principles calculations based on density functional theory, and the calculated equilibrium structural parameters were in good agreement with the available experimental data.
Journal ArticleDOI
Using ab initio calculations in designing bcc Mg–Li alloys for ultra-lightweight applications
TL;DR: In this article, single crystal elastic constants of 11 bcc Mg-Li alloys are calculated using density functional theory and compared with available experimental data based on DFT determined properties.
Journal ArticleDOI
Brittle and ductile fracture of semiconductor nanowires – molecular dynamics simulations
Keonwook Kang,Wei Cai +1 more
TL;DR: In this paper, a simple parameter based on the ratio between the ideal tensile strength and the ideal shear strength is found to correlate very well with the observed brittle versus ductile behaviors for all the potentials used in this study.
References
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Journal ArticleDOI
Beitrag zur Theorie des Anlaufvorgangs
TL;DR: The Mechanismus des Diffusionsvorgangs is still weitgehend unbekannt as discussed by the authors, i.e., the Diffusion of mindestens einem der beiden Bestandteile durch die Anlaufschicht is notwendig.
Journal ArticleDOI
The diffusion of 63Ni along grain boundaries in nickel oxide
A. Atkinson,R. I. Taylor +1 more
TL;DR: The product of the grain boundary diffusion coefficient and width, D′δ, has been measured directly for the diffusion of 63Ni along grain boundaries in high-purity NiO as discussed by the authors.
Journal ArticleDOI
The role of oxide microstructure and growth stresses in the high-temperature scaling of nickel
F. N. Rhines,J. S. Wolf +1 more
TL;DR: In this article, the formation of new nickel oxide upon boundaries of columnar grains where nickel diffusing through the oxide crystals, meets oxygen, diffusing along grain boundaries is identified as the primary cause of this stress.
Journal ArticleDOI
The diffusion of Ni in the bulk and along dislocations in NiO single crystals
A. Atkinson,R. I. Taylor +1 more
TL;DR: In this paper, diffusion profiles of 63Ni tracer in single crystals of NiO following anneals at 522°-1000°C have been determined by a radio-frequency sputter-sectioning technique.
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