Download or read book Mechanical Properties of Zirconium Alloys and Zirconium Hydrides Predicted from Density Functional Perturbation Theory written by and published by . This book was released on 2015 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, 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 Pn-3m with combining macron]m polymorph of [delta]-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 [alpha]-Zr, Zr-alloy and Zr-hydride polycrystalline aggregates is limited by the shear modulus. According to both Pugh's and Poisson's ratios, [alpha]-Zr, Zr-alloy and Zr-hydride polycrystalline aggregates can be considered ductile. The Debye temperatures predicted for [gamma]-ZrH, [delta]-ZrH1.5 and [epsilon]-ZrH2 are [theta]D = 299.7, 415.6 and 356.9 K, respectively, while [theta]D = 273.6, 284.2, 264.1 and 257.1 K for the [alpha]-Zr, Zry-4, ZIRLO and M5 matrices, i.e. suggesting that Zry-4 possesses the highest micro-hardness among Zr matrices.

Download or read book The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components written by Manfred P. Puls and published by Springer Science & Business Media. This book was released on 2012-08-04 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: By drawing together the current theoretical and experimental understanding of the phenomena of delayed hydride cracking (DHC) in zirconium alloys, The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking provides a detailed explanation focusing on the properties of hydrogen and hydrides in these alloys. Whilst the emphasis lies on zirconium alloys, the combination of both the empirical and mechanistic approaches creates a solid understanding that can also be applied to other hydride forming metals. This up-to-date reference focuses on documented research surrounding DHC, including current methodologies for design and assessment of the results of periodic in-service inspections of pressure tubes in nuclear reactors. Emphasis is placed on showing how our understanding of DHC is supported by progress in general understanding of such broad fields as the study of hysteresis associated with first order phase transformations, phase relationships in coherent crystalline metallic solids, the physics of point and line defects, diffusion of substitutional and interstitial atoms in crystalline solids, and continuum fracture and solid mechanics. Furthermore, an account of current methodologies is given illustrating how such understanding of hydrogen, hydrides and DHC in zirconium alloys underpins these methodologies for assessments of real life cases in the Canadian nuclear industry. The all-encompassing approach makes The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Component: Delayed Hydride Cracking an ideal reference source for students, researchers and industry professionals alike.

Download or read book Predicting the Equilibria of Point Defects in Zirconium Oxide written by Mostafa Youssef Mahmoud Youssef and published by . This book was released on 2014 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of zirconium alloys in nuclear reactors is compromised by corrosion and hydrogen pickup. The thermodynamics and kinetics of these two processes are governed by the behavior of point defects in the ZrO2 layer that grows natively on these alloys. In this thesis, we developed a general, broadly applicable framework to predict the equilibria of point defects in a metal oxide. The framework is informed by density functional theory and relies on notions of statistical mechanics. Validation was performed on the tetragonal and monoclinic phases of ZrO2 by comparison with prior conductivity experiments. The framework was applied to four fundamental problems for understanding the corrosion and hydrogen pickup of zirconium alloys. First, by coupling the predicted concentrations of oxygen defects in tetragonal ZrO2 with their calculated migration barriers, we determined oxygen self-diffusivity in a wide range of thermodynamic conditions spanning from the metal-oxide interface to the oxide-water interface. This facilitates future macro-scale modeling of the oxide layer growth kinetics on zirconium alloys. Second, using the computed defect equilibria of the tetragonal and monoclinic phases, we constructed a temperature-oxygen partial pressure phase diagram for ZrO2. The diagram showed that the tetragonal phase can be stabilized below its atmospheric transition-temperature by lowering the oxygen chemical potential. This work adds a new explanation to the stabilization of the tetragonal phase at the metal-oxide interface where the oxygen partial pressure is low. Third, using the developed framework, we modeled co-doping of monoclinic ZrO2 with hydrogen and a transition metal. Our modeling predicted a volcano-like dependence of hydrogen (proton) solubility on the first-row transition metals, which is consistent with a set of systematic experiments from the nuclear industry. We discovered that the reason behind this behavior is the ability of the transition metal to p-type-dope ZrO2 and hence lower the chemical potential of electron. Therefore, the peak of the hydrogen solubility in monoclinic ZrO2 also corresponds to an increased barrier for hydrogen gas evolution on the surface. This explanation opens the door to physics-based design of resistant zirconium alloys, and qualitatively consistent with the monoclinic ZrO2. Finally, we uncovered the interplay between certain hydrogen defects and planar compressive stress which tetragonal ZrO2 experiences on zirconium alloys. The stress enhances the abundance of these defects, while these same defects tend to relax the stress. This interplay was used to propose an oxide fracture mechanism by which hydrogen is picked up.

Download or read book Mechanical Characterization of Zirconium Hydrides with High Energy X Ray Diffraction written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Zirconium and its alloys are of technical importance, finding application as a structural material in the nuclear industry. Engineering components fabricated from zirconium slowly pick-up hydrogen as a result of in-reactor corrosion, degrading the components mechanical properties as a brittle hydride phase forms. This dissertation applies high energy X-ray diffraction to directly measure the mechanical properties of zirconium hydrides in the bulk and at stress concentrations in zirconium alloys. The current study is presented as a manuscript format dissertation comprised of three manuscript chapters. Chapter 3 reports the in-situ loading of hydrided Zircaloy-2 and discusses hydride/Zircaloy-2 matrix interactions as a function of applied load. Chapter 4 reports the mechanical behavior at a fatigue pre-crack in un-hydrided Zircaloy-2, comparing the results to finite element and polycrystalline plasticity models of the crack tip. Chapter 5 reports the effect of hydrides on the notch tip strain field. The three manuscript chapters are followed by a general discussion in Chapter 6 and conclusions in Chapter 7.

Download or read book The mechanical properties of zirconium alloys written by E. F. Ibrahim and published by . This book was released on 1969 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydrogen Migration and Mechanical Behavior of Hydrided Zirconium Alloys written by Soyoung Kang and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zirconium alloys have been widely used for nuclear fuel cladding materials in light-water nuclear reactors. The cladding corrodes as a result of exposure to the coolant water and produces hydrogen as a result of the corrosion reaction. A fraction of this hydrogen can be picked up into the cladding material. Once the hydrogen content reaches the terminal solid solubility, zirconium hydride particles start to precipitate. The cladding suffers waterside corrosion in service, leading to hydrogen ingress, which can redistribute in the cladding and form hydrides. Because these zirconium hydrides are more brittle than the zirconium matrix, they can deteriorate the ductility of the cladding. Therefore, understanding hydrogen behavior in cladding is important to maintain cladding integrity. This study aims to investigate hydrogen migration under a temperature gradient and mechanical behavior of hydrided zirconium alloys. The hydrogen transport and hydride precipitation /dissolution model HNGD was implemented in the fuel performance code BISON to predict hydrogen behavior. The hydrogen is distributed inhomogeneously in the cladding as a result of Fick's law and Soret effect. The hydrogen tends to move from higher to lower concentration governed by Fick's law and higher to lower temperature based on the Soret effect. Hydrogen migration tests were designed to determine the heat of transport value (Q*) of hydrogen in Zr, a parameter needed to evaluate the Soret effect. Hydrided samples were subjected to a long annealing schedule in a temperature gradient to re-distribute the hydrogen. The annealed samples were cut into several pieces along the temperature gradient, and the hydrogen contents were analyzed using hot vacuum extraction. The hydrogen distribution along the temperature gradient was observed in this experiment, and from this data, the heat of transport value (Q*) was determined. Further, the mechanical behavior of zirconium alloys was assessed using ring compression tests. The zirconium alloy tubes were characterized by electron backscatter diffraction (EBSD) to identify the microstructure of materials. Stress relieved anneal ZIRLO (SRA) and low Sn Partially recrystallized anneal LT ZIRLO (PRXA) show different grain shapes and sizes. After characterization, the zirconium alloy tubes were hydrogen charged and cut into 8 mm length rings. The ring samples were subjected to compression at 12 o'clock following a specified thermomechanical cycle. This thermomechanical treatment caused partial precipitation of radial hydrides in certain positions of the ring samples. The radial hydride fractions were characterized and showed a difference between ZIRLO and LT ZIRLO because of their different microstructures. Finite element modeling conducted using ABAQUS could then determine the threshold stress for two materials by comparing simulation results (stress state) and hydride morphologies. In addition, the ring compression tests for assessing hydrided cladding ductility for various hydride morphologies were conducted at room temperature. Ring samples with different radial hydride continuity factors (RHCF) were tested to determine their load-displacement curves. The 1% permanent strain and 2 % offset strain criteria were chosen to assess the ductility of samples. The ductility degrades with increasing RHCF.

Download or read book Transformation Reactions and Mechanical Properties of Zirconium Alloys Containing Copper and Molybdenum written by and published by . This book was released on 1960 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: At the present time, zircaloy is generally considered to be the most attractive material available for water-cooled power reactor fuel cladding and core components such as pressure tubes, but projected power reactor designs already require a better material having improved mechanical properties and corrosion resistance at the higher operating temperatures contemplated. As part of the Canadian program directed toward natural uranium fuelled power reactor development, a study of zirconium-based alloys containing between 1 and 2 wt% copper, combined with from 1.5 to 2.5 wt% molybdenum was made. In this investigation, the effects of solution and ageing heat treatments were examined in metallographic structure and resulting room temperature mechanical properties. An assessment of hot working fabrication characteristics was also made.

Download or read book U S Government Research Reports written by and published by . This book was released on 1962 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanical Properties of Zirconium written by F. D. Rosi and published by . This book was released on 1952 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1969 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydrides for Energy Storage written by A. F. Andresen and published by Elsevier. This book was released on 2013-10-22 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrides for Energy Storage documents the proceedings of an International Symposium held in Geilo, Norway on August 14-19, 1977. This book discusses the thermodynamics of metal, alloy and intermetallic/hydrogen systems; localization and diffusion of hydrogen in lanthanum-nickel compounds; kinetics of hydrogen absorption and desorption; and nuclear magnetic resonance studies of metal hydrides. The calculated heats of formation of metal and metal alloy hydrides; hydrogen absorption into rare earth intermetallic compounds; plateau pressure of RE Ni5 and RE Co5 hydrides; and hydride formation of C14-type Ti alloy are also elaborated. This text likewise covers the mixing effects of two different types of hydrides; hydrogen storage electrode systems; and applications of metal hydrides. This publication is intended for chemists concerned with the fundamental properties of hydrides.

Download or read book High Temperature Oxidation and Corrosion of Metals written by David John Young and published by Elsevier. This book was released on 2008-10-03 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is concerned with understanding the fundamental mechanisms of high temperature alloy oxidation. It uses this understanding to develop methods of predicting oxidation rates and the way they change with temperature, gas chemistry and alloy composition. The focus is on designing (or selecting) alloy compositions which provide optimal resistance to attack by corrosive gases. . Emphasises quantitative calculations for predicting reaction rates and the effects of temperature, oxidant activities and alloy compositions. . Uses phase diagrams and diffusion paths to analyse and interpret scale structures and internal precipitation distributions . Provides a detailed examination of corrosion in industrial gases (water vapour effects, carburisation and metal dusting, sulphidation) . Text is well supported by numerous micrographs, phase diagrams and tabulations of relevant thermodynamic and kinetic data . Combines physical chemistry and materials science methodologies.

Download or read book Technical Abstract Bulletin written by Defense Documentation Center (U.S.) and published by . This book was released on 1963 with total page 1032 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Glenn Coefficients for Calculating Thermodynamic Properties of Individual Species written by Bonnie J. McBride and published by . This book was released on 2002 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1981 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Structural Chemistry written by Stepan S. Batsanov and published by Springer Science & Business Media. This book was released on 2012-11-29 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: A concise description of models and quantitative parameters in structural chemistry and their interrelations, with 280 tables and >3000 references giving the most up-to-date experimental data on energy characteristics of atoms, molecules and crystals (ionisation potentials, electron affinities, bond energies, heats of phase transitions, band and lattice energies), optical properties (refractive index, polarisability), spectroscopic characteristics and geometrical parameters (bond distances and angles, coordination numbers) of substances in gaseous, liquid and solid states, in glasses and melts, for various thermodynamic conditions. Systems of metallic, covalent, ionic and van der Waals radii, effective atomic charges and other empirical and semi-empirical models are critically revised. Special attention is given to new and growing areas: structural studies of solids under high pressures and van der Waals molecules in gases. The book is addressed to researchers, academics, postgraduates and advanced-course students in crystallography, materials science, physical chemistry of solids.

Download or read book Bibliography of Scientific and Industrial Reports written by and published by . This book was released on 1962 with total page 1722 pages. Available in PDF, EPUB and Kindle. Book excerpt: