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Showing papers on "Zirconium alloy published in 2019"


Journal ArticleDOI
TL;DR: In this article, the first generation of chromium-based coatings exhibited the most promising behavior: good compromise between oxidation resistance and adhesion to the metallic substrate, good fretting resistance and improved resistance to oxidation in steam at high temperature.

172 citations


Journal ArticleDOI
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


Journal ArticleDOI
TL;DR: In this paper, the microstructure, corrosion resistance and oxidation behavior of Zircaloy-4 samples were investigated by vacuum arc plasma deposition and their as-received coating is dense with no pores or defects observed.

102 citations


Journal ArticleDOI
TL;DR: A review of the evolution in measurement methodologies (either from controlled experiments in materials test reactors or gauging of power reactor components) is described together with the results gleaned from such measurements.

84 citations


Journal ArticleDOI
TL;DR: In this article, a cold spray process for the deposition of chromium (Cr) coatings on zirconium-alloys is presented with the goal of improving the accident tolerance of light water reactor (LWR) fuel cladding tubes.

75 citations


Journal ArticleDOI
TL;DR: In this paper, the authors introduced Mo as a buffer layer and significantly reduced the inter-diffusion of zirconium and iron to improve the performance of thin FeCrAl coatings.

58 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed a model to understand the effects of localized stress fields on hydrogen diffusion and precipitation in zirconium polycrystals, where a crystal plasticity finite element code was updated and coupled with a series of newly developed subroutines for simulating stress-assisted diffusion of hydrogen atoms in polycrystalline polymers.

36 citations


Journal ArticleDOI
TL;DR: In this paper, two FeCrAl alloy coatings with different Cr and Al contents were deposited on Zr-alloy substrates via the cold spray deposition method to study the efficacy of these coatings to improve the accident tolerance of Zralloy fuel cladding in light water reactors (LWRs).
Abstract: Two FeCrAl alloy coatings with different Cr and Al contents were deposited on Zr-alloy substrates via the cold spray deposition method to study the efficacy of these coatings to improve the accident tolerance of Zr-alloy fuel cladding in light water reactors (LWRs). First, the coatings were tested in a 400 °C steam autoclave for 72 h as an accelerated method to simulate the normal LWR operating conditions. In these tests, both coatings resulted in notable improvements in oxidation resistance compared to the Zr-alloy, with the higher Cr containing coating exhibiting a thinner oxide layer. Both coatings provided good oxidation resistance when tested in 1200 °C ambient air environment; however, the formation of a low melting point eutectic (~928 °C) between Fe and Zr resulted in significant melting associated with inter-diffusion between Fe in the coating and the Zr in the substrate. Therefore, to take advantage of the superior oxidation resistance that FeCrAl coatings can provide, a Mo interlayer was deposited, also by the cold spray process, in-between the protective FeCrAl coating and the Zr-alloy substrate, thus creating a dual cold spray layer accident tolerant coated cladding concept. The wear resistance of the FeCrAl coating was superior to the Zr-alloy substrate based on pin-on-disk wear tests, providing an indication of the benefits of such coatings to reduce grit-to-rod fretting (GTRF) damage. The feedstock powders, microstructure, phases, hardness of coatings, as well as oxide and inter-diffusion layers of oxidized coatings were examined using SEM, XRD, and XPS characterization techniques.

36 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used atom probe tomography (APT) analysis of hydrogen in zirconium alloy systems that are important for nuclear power applications, and discussed possible ways to ensure that appropriate information is extracted from APT analysis.
Abstract: Analysis and understanding of the role of hydrogen in metals is a significant challenge for the future of materials science, and this is a clear objective of recent work in the atom probe tomography (APT) community Isotopic marking by deuteration has often been proposed as the preferred route to enable quantification of hydrogen by APT Zircaloy-4 was charged electrochemically with hydrogen and deuterium under the same conditions to form large hydrides and deuterides Our results from a Zr hydride and a Zr deuteride highlight the challenges associated with accurate quantification of hydrogen and deuterium, in particular associated with the overlap of peaks at a low mass-to-charge ratio and of hydrogen/deuterium containing molecular ions We discuss possible ways to ensure that appropriate information is extracted from APT analysis of hydrogen in zirconium alloy systems that are important for nuclear power applications

36 citations


Journal ArticleDOI
TL;DR: In this article, the thermal shock resistance (TSR) tests were carried out in three temperature variations, that is, △T =※800 °C, 1000´°C and 1200´ºC, respectively, and the results showed that TiN coating was partially peeled off and the inner zirconium alloy was oxidized.

35 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used transmission electron microscopy to study the type, distribution, concentration and connectivity of nano-porosity as a function of depth through the oxide layer.

Journal ArticleDOI
TL;DR: In this paper, a Ti2AlC MAX phase material was deposited on Zircaloy-4 substrate using the cold spray process, with the goal of enhancing the accident tolerance of zirconium-alloy fuel cladding in light water reactors.

Journal ArticleDOI
15 Apr 2019-Wear
TL;DR: In this article, the effect of micro-arc oxidation (MAO) on the fretting wear behavior of a reactor-grade zirconium alloy known as ZIRLO™ was investigated.

Journal ArticleDOI
TL;DR: In this article, three sets of Cr coatings on a Zr alloy with thickness of 5, 10 and 12μm have been irradiated at 400°C with 6'MeV Au ions to average doses of 10, 25 and 50 dpa.

Journal ArticleDOI
TL;DR: In this article, the role of Nb on Zr-Nb oxidation kinetics was investigated using nano-beam X-ray absorption near-edge spectroscopy (XANES), transmission electron microscopy (TEM), and application of Coupled-current charge-compensation (C4) Model.

Journal ArticleDOI
TL;DR: In this article, the authors studied the microstructural evolution and the high-temperature high-pressure corrosion behavior of N18 zirconium alloy prior and after high-current pulsed electron beam (HCPEB) surface irradiation.

Journal ArticleDOI
TL;DR: In this paper, the distribution, morphology and structure of zirconium hydrides formed using different cooling rates through the solid state Zr+[H] → Zr−+hydride transus, in fine and blocky alpha Zircaloy-4.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the relationship between t-ZrO2 and undulated interface and found that the tetragonal phase is mainly distributed near the metal/oxide interface.

Journal ArticleDOI
TL;DR: In this article, the effects of irradiation temperature on the damage structures that form during proton-irradiation has been carried out on two commercial Zr alloys in order to develop a more mechanistic understanding of the effect of niobium on dislocation loop evolution.

Journal ArticleDOI
TL;DR: In this paper, a duplex cladding, with a 150μm external layer of low-tin Zircaloy-4, so-called liner, bonded to an inner standard substrate, was measured using a state-of-the-art neutron imaging setup of PSI Neutron Microscope with an effective spatial resolution of 9.6

Journal ArticleDOI
TL;DR: In this paper, a detailed analysis of barrier layer nano-porosity by TEM and TKD has revealed that the oxide grain structure is much more disorganised and the nanoporosity network better developed in the rapidly oxidising post-transition alloy.

Journal ArticleDOI
TL;DR: In this article, the cladding substrate, Zircaloy-4 was coated with a 3-μm zirconium silicide (ZrSi2) to prevent thermal oxidation.

Journal ArticleDOI
TL;DR: In this article, the effects of oxygen isotopic substitution were examined in terms of disorder and size-related effects on thin zirconia layers grown on Zirconium alloys simulating in-reactor materials.
Abstract: Recently, unusual Raman signals were observed in different works conducted on thin zirconia layers grown on zirconium alloys simulating in‐reactor materials after high fluence ion irradiation or for samples cut from fuel rods irradiated in nuclear plants. As such, these spectra clearly do not correspond to any known spectrum of a pure standard zirconia phase. Therefore, the analysis conducted in this paper aims to provide a better understanding of these peculiar Raman features. For that purpose, specific ion‐irradiated samples were analysed. In situ Raman spectroscopy was first used to follow the irradiation process. Then, samples were characterized using different excitation wavelengths. Finally, the effects of oxygen isotopic substitution were examined in details. Results are discussed in terms of disorder and size‐related effects.

Journal ArticleDOI
TL;DR: In this paper, the effect of pre-existing oxide layer formed at low temperature on the subsequent oxidation in steam at high temperature was studied for Zircaloy-4 and M5Framatome alloys.

Journal ArticleDOI
TL;DR: In this paper, a ZrO2/CrN composite film was successfully prepared on Zr-4 alloy by plasma electrolytic oxidation (PEO) and plasma immersion ion implantation and deposition (PIII&D) methods.
Abstract: In this paper, a ZrO2/CrN ceramic composite film was successfully prepared on Zr-4 alloy by plasma electrolytic oxidation (PEO) and plasma immersion ion implantation and deposition (PIII&D) methods. The morphology, phase structure and composition of the ceramic composite film were analyzed. The in-situ high-temperature electrochemical behavior was investigated in borated and lithiated high temperature water by a dynamic high-temperature-high-pressure electrochemical analysis system. The results showed that the ZrO2/CrN film exhibited a good corrosion resistance at both room temperature and high temperature, though the protective property of the film degraded with increasing temperature. When the temperature exceeded 200 °C, the outer CrN film turned into Cr2O3 by the thermal oxidation process, and the new formed ZrO2/Cr2O3 composite film shows an excellent stability for the longstanding corrosion protection.

Journal ArticleDOI
TL;DR: In this paper, the effects of hydrides on the Zircaloy-4 (α-(hcp)-Zr) tensile properties, together with an in-depth study of any relationship between tensile and the microstructural properties of the material, are discussed.
Abstract: The use of zirconium alloys such as Zircaloy-4 in nuclear reactors is limited by brittle hydride formation, for example in harsh reactor operating conditions such as those in the pressurized water reactors. Even though much research has studied this phenomenon, a more systematic, in-depth study of the effects of hydrides on the properties of Zircaloy-4, using various analytical techniques, can add more details to the understanding of these effects. In the current study, hydrogen charging was performed on Zircaloy-4 at different levels compatible with commercial reactor operating conditions and conditions in accident scenarios. Effects of hydriding on the Zircaloy-4 (α-(hcp)-Zr) tensile properties, together with an in-depth study of any relationship between tensile and the microstructural properties of the material, are discussed. While a moderate pinning effect on the equiaxed α-Zr grain size was observed, no significant change in bulk texture of the Zry-4 was revealed as the hydrogen level increased up to nominally 1230 wppmH. At a nominal value of 490 wppmH, Zircaloy-4 fractured at a low strain value just above the yielding point, and brittle tensile fracture was observed in a sample H-charged to nominally 1230 wppmH. The low ductility and brittle fracture of the samples were attributed to the presence of brittle inter-grain boundary hydrides. It was observed that brittle fracturing was also supported by intra-grain boundary hydrides that were affected by the tensile deformation of the sample.

Journal ArticleDOI
TL;DR: In this paper, a method based on 3D mapping by high-resolution SIMS was proposed to measure the distribution of deuterium in oxidised Zircaloy-4 alloy samples.

Journal ArticleDOI
TL;DR: In this paper, the performance of a Zr-0.5Nb and an annealed Zr1.0Nb alloys were measured during corrosion in pure water autoclave (360'C, 18'MPa).

Journal ArticleDOI
Haixia Jiang1, Zewen Duan1, Xiaoyu Zhao1, Beibei Zhang1, Peng Wang1 
TL;DR: In this paper, the impact of ion irradiation on the microstructure evolution, mechanical and tribological behaviors of Zr-4 alloy was investigated using HRTEM observations.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the oxidation behavior of pure zirconium and its alloys in the Transient Reactor Test (TREAT) facility at Idaho National Laboratory.
Abstract: The Transient Reactor Test (TREAT) facility at the Idaho National Laboratory currently utilizes a legacy Zircaloy-3 cladding, which is no longer commercially available. TREAT is air cooled and routinely operates at temperatures well above that of traditional reactor designs. This study investigates the oxidation behavior of pure zirconium and its alloys (Zircaloy-3, Zircaloy-4, Zr-1Nb, Zr-2.5Nb) in Ar+20%O2 and N2+20%O2 atmospheres at temperatures ranging from 400–800 °C to determine which alloy should be implemented as TREAT's cladding. While the oxidation behavior of zirconium based cladding materials has been extensively documented, this study focuses on direct comparison between legacy Zircaloy-3 and contemporary alloys using a flat plate geometry and similar conditions seen at the TREAT facility. In this work, thermogravimetric analysis was used to measure both steady state and breakaway oxidation, which was then used to calculate oxidation rate constants and activation energies of each material. Oxide thickness was evaluated through microscopy of oxidized specimen cross sections. The Zircaloy-3 and Zr-1Nb alloys were found to be the most resistant to oxidation under the conditions of this study, whereas the Zr-2.5Nb alloy was found to be the most susceptible.