Author
Anna-Maria Alvarez Holston
Bio: Anna-Maria Alvarez Holston is an academic researcher. The author has contributed to research in topics: Ab initio & Zirconium. The author has an hindex of 4, co-authored 5 publications receiving 97 citations.
Papers
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TL;DR: In this paper, a systematic ab initio study of the elastic and thermodynamic properties of γ -ZrH, δ - ZrH 1.5, γ-ZrD, and δ − ZrD 2.5 was performed using the frozen core projector augmented wave (PAW) approach and a generalised gradient approximated (GGA) exchange correlation functional.
63 citations
TL;DR: In this paper, an ab initio study of the influence of hydrogen filled vacancies on the mechanical properties of zirconium was carried out and the results of the modelling imply that the work of fracture and peak stress decrease as a result of the presence of hydrogen-filled vacancies.
27 citations
TL;DR: In this paper, the hardness and Youngs modulus in the hydride and matrix of a high burn-up neutron-irradiated Zircaloy-2 cl...
25 citations
TL;DR: In this paper, the authors report the results of an ab initio study of the transgranular fracture toughness and cleavage of brittle zirconium hydrides, using the Griffith-Irwin relation to assess the fractur...
Abstract: In this work we report the results of an ab initio study of the transgranular fracture toughness and cleavage of brittle zirconium hydrides. We use the Griffith–Irwin relation to assess the fractur ...
10 citations
TL;DR: In this article, the delayed hydride cracking (DHC) behavior of PWR spent fuel cladding due to the limited data of KIH (i.e., threshold stress intensity factor), especially for irradiated claddings, was investigated.
2 citations
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TL;DR: In this article, the authors review the processes of hydrogen transport, hydride precipitation and dissolution and formation of mesoscale hydrides, and highlight where more research is needed, both from an experimental and from a modeling point of view.
161 citations
TL;DR: In this paper, the authors provide a concise summary of experimental and computational studies performed on hydride precipitation in zirconium alloys since the 1960's, with specific consideration given to the phase field model, which has become a popular and powerful computational tool for modeling microstructure evolution.
106 citations
TL;DR: By including the temperature-dependent terms of the free energy based on ab initio calculations, hydrogen adsorption isotherms are computed and shown to be in good agreement with experimental data.
Abstract: Structural, thermodynamic and elastic properties of the hydrogen?zirconium system including all major hydrides are studied from first principles. Interstitial hydrogen atoms occupy preferentially tetrahedral sites. The calculations show that a single vacancy in ?-Zr can trap up to nine hydrogen atoms. Self-interstitial Zr atoms attract hydrogen to a lesser extent. Accumulation of hydrogen atoms near self-interstitials may become a nucleation site for hydrides. By including the temperature-dependent terms of the free energy based on ab initio calculations, hydrogen adsorption isotherms are computed and shown to be in good agreement with experimental data. The solubility of hydrogen decreases in Zr under compressive strain. The volume dependence on hydrogen concentration is similar for hydrogen in solution and in hydrides. The bulk modulus increases with hydrogen concentration from 96 to 132?GPa.
61 citations
TL;DR: Results show that the lowest-energy cubic Pn3[combining macron]m polymorph of δ-ZrH1.5 does not satisfy all the Born requirements for mechanical stability, unlike its nearly degenerate tetragonal P42/mcm polymorph.
Abstract: The elastic properties and mechanical stability of zirconium alloys and zirconium hydrides have been investigated within the framework of density functional perturbation theory. Results show that the lowest-energy cubic Pnm polymorph of δ-ZrH1.5 does not satisfy all the Born requirements for mechanical stability, unlike its nearly degenerate tetragonal P42/mcm polymorph. Elastic moduli predicted with the Voigt–Reuss–Hill approximations suggest that mechanical stability of α-Zr, Zr-alloy and Zr-hydride polycrystalline aggregates is limited by the shear modulus. According to both Pugh's and Poisson's ratios, α-Zr, Zr-alloy and Zr-hydride polycrystalline aggregates can be considered ductile. The Debye temperatures predicted for γ-ZrH, δ-ZrH1.5 and e-ZrH2 are θD = 299.7, 415.6 and 356.9 K, respectively, while θD = 273.6, 284.2, 264.1 and 257.1 K for the α-Zr, Zry-4, ZIRLO and M5 matrices, i.e. suggesting that Zry-4 possesses the highest micro-hardness among Zr matrices.
52 citations
TL;DR: In this paper, a detailed analysis of peak widths measured for different crystal planes was carried out and it was shown that most of the broadening is the result of dislocations.
47 citations