Showing papers on "Zirconium alloy published in 2021"
TL;DR: In this paper, the Cr-Zr interaction of two types of Cr coated Zr alloy accident tolerant fuel (ATF) claddings, deposited by cold spraying and magnetron sputtering, was studied in argon in the temperature range from 1100 to 1300°C.
59 citations
TL;DR: In this paper, the authors introduce the latest results in the development of protective coatings for ATF claddings based on Zr alloys, involving their behavior under normal and accident conditions in light water reactors (LWRs).
Abstract: Zirconium-based alloys have served the nuclear industry for several decades due to their acceptable properties for nuclear cores of light water reactors (LWRs). However, severe accidents in LWRs have directed research and development of accident tolerant fuel (ATF) concepts that aim to improve nuclear fuel safety during normal operation, operational transients and possible accident scenarios. This review introduces the latest results in the development of protective coatings for ATF claddings based on Zr alloys, involving their behavior under normal and accident conditions in LWRs. Great attention has been paid to the protection and oxidation mechanisms of coated claddings, as well as to the mutual interdiffusion between coatings and zirconium alloys. An overview of recent developments in barrier coatings is introduced, and possible barrier layers and structure designs for suppressing mutual diffusion are proposed.
44 citations
TL;DR: In this article, a comprehensive review on the corrosion behavior of FeCrAl alloys including oxidation kinetics, corrosion processes and influencing factors in nuclear reactors is presented, and the challenges and prospects of the commercial application of Fe-CrAl cladding are concluded.
33 citations
TL;DR: In this article, a review summarizes the published data on the widely applied electron-beam, laser-beam as well as resistance upset, projection, and spot welding of zirconium alloys for nuclear applications.
26 citations
TL;DR: In this article, the feasibility of Cr2AlC MAX phase as a protective coating on zirconium-alloy fuel claddings was explored focusing on high-temperature oxidation resistance in steam and hydrothermal corrosion performance in autoclave.
Abstract: Alumina-forming MAX phase coatings reveal great potential for accident tolerant fuel (ATF) cladding applications due to their favorable physical and mechanical properties and excellent high-temperature oxidation resistance. The feasibility of Cr2AlC MAX phase as protective coating on zirconium-alloy fuel claddings was explored focusing on high-temperature oxidation resistance in steam and hydrothermal corrosion performance in autoclave. Single-phase and basal-plane textured Cr2AlC coatings (~6 μm thick) were synthesized on Zircaloy-4 substrate by thermal annealing of specifically designed, magnetron-sputtered Cr/C/Al elemental multilayers at 550 °C for 10 min. Additionally, a second Cr/Cr2AlC bilayer coating design was fabricated aiming to eliminate potential rapid hydrothermal dissolution of Al during normal operating conditions. Micro-cracking appeared on both annealed coatings owing to thermal expansion differences between coating layer and substrate. Growth of an adherent and dense α-Al2O3 scale during high-temperature oxidation in steam and of a thin passivating Cr2O3 layer during hydrothermal corrosion in an autoclave imply excellent combined oxidation and corrosion resistance of the textured Cr2AlC coatings on Zircaloy-4. A self-healing capability via growth of alumina filling the micro-crack (annealing-induced) gaps was observed during high-temperature oxidation. However, partial delamination was seen for both coatings after short autoclave exposure and their mechanical properties (fracture toughness and adhesion strength) need further enhancement. Overall, tailored Cr2AlC-based (multilayered) coatings can be attractive candidates as potential type of coated ATF claddings.
24 citations
TL;DR: In this article, a review of the biological applications of uncoated zirconium is presented, an introduction of the coating procedure will be presented, and the bioactive and biocompatibility behavior of deposited coatings on Zr using the PEO technique will be evaluated.
24 citations
TL;DR: In this article, the most relevant results on high-energy surface modification of zirconium and its alloys have been published, which include laser processing, high-current pulsed electron beam irradiation, ion implantation and plasma treatment.
18 citations
TL;DR: In this paper, the effects of oxidation and inter-diffusion on the fracture mechanisms of Cr-coated Zry-4 alloys were conducted in situ three-point bending tests were observed in real time.
18 citations
TL;DR: In this article, a nickel-based alloy 718 against a zirconium alloy in the range 25-30°C was compared to room temperature, and it was found that the wear coefficient of ZrO2 increases significantly at a transition temperature Ttr ~250-260°C, which is consistent with published data.
18 citations
TL;DR: In this article, the preferential orientation of Cr coatings has been regulated in order to enhance the oxidation resistance of the coatings with different textures, and a transition layer and dispersed particles with higher oxygen content have been discovered after oxidizing in steam at 800 ℃ for 1 h.
16 citations
TL;DR: In this article, an overview of publications on arc welding of zirconium and its alloys for seven decades is provided, where the main attention is paid to the parameters of the gas tungsten arc, plasma arc, and gas metal arc welding methods.
TL;DR: In this article, a combination of electron back-scattered diffraction and atom probe tomography was used to investigate specific microstructural features from the as-received sample and in the blocky-α microstructure, before and after electrochemical charging with hydrogen/deuterium followed by a low temperature heat treatment at 400°C for 5h followed by furnace cooling at a rate of 0.5°C/min.
TL;DR: TRANOX-1.0 (TRANsient OXidation), a mechanistic model that calculates oxygen distribution for isothermal and non-isothermal transients (1000-1250°C) has been developed as mentioned in this paper.
TL;DR: In this article, a preplaced Ta Zr alloy powder layer (Ta:Zr = 7:3 in wt%) is coated on a Ti6Al4V substrate by laser-based directed energy deposition.
Abstract: In this work, a preplaced Ta Zr alloy powder layer (Ta:Zr = 7:3 in wt%) is coated on a Ti6Al4V substrate by laser-based directed energy deposition. Crack-free, smooth Ta Zr alloy coating is acquired, and the content of elements (Ta, Zr, Ti, Al, V) distributes in a gradient. In this coating, the bcc α-Ta grains with a rectangular shape and a size of 10–20 nm surrounded by the TiZr phase, the Al3Zr4 phase mainly gathers in grain boundary. The corrosion resistance of the coating and substrate is tested via electrochemical measurement and the coating exhibits a better resistance in 0.5 mol/L H2SO4 solution. The average microhardness of the coating is around 600 HV, which is ~1.7 times than that of the substrate. The wear test results show the mass loss of the coating is approximately 60 times lower than the substrate at room temperature. It is believed that this coating could shed light on not only the protection of Ti-based alloy, but also the Fe-based and Ni-based components with the functionally graded transition layers.
TL;DR: In this paper, the micro-arc oxidation (MAO) coating with different nanoparticles (Al2O3, MoS2, CeO2, and graphene oxide (GO)) was prepared on zirconium (Zr) alloy.
Abstract: The micro-arc oxidation (MAO) coating with different nanoparticles (Al2O3, MoS2, CeO2, and graphene oxide (GO)) was prepared on zirconium (Zr) alloy. The surface morphology, cross-section morphology, element composition, and phase structure of different composite MAO coating were investigated. Results show the composite MAO coating consists of ZrO2 and nanoparticle, along with all the coating present a typical porous structure. The composite MAO coating is comprised of an outer porous layer and inner dense layer, and most of the nanoparticle is gathered to the outer layer. The electrochemical results demonstrate that composite MAO coating presents better corrosion protection to Zr alloy, and the MAO coating with Al2O3 shows the best corrosion resistance. Because the Al2O3 nanoparticle can stabilize the t-ZrO2 during MAO process and has a denser inner layer. Meanwhile, the nanoparticles in the coating can play the part of a barrier to the diffusion pathway of corrosion medium and restrain aggressive corrosion medium entering the Zr alloy. The fretting corrosion test shows that the MAO coating with GO has the lowest wear volume, and it has the highest material loss volume ratio of corrosion induced by wear. Because GO in MAO coating can reduce the friction by small shear force between the layers.
TL;DR: In this paper, the corrosion behavior of Zircaloy-4 (Zry-4) at 360 °C 0.01 M LiOH aqueous solution was in-situ monitored by electrochemical impedance spectroscopy (EIS).
TL;DR: In this paper, the authors investigated the oxidation behavior of five CrAl-based coatings containing different amounts of Al deposited onto Zr-4 alloy exposed to high-temperature air and demonstrated that pure Cr coating exhibits excellent oxidation resistance due to the formation of dense and continuous Cr2O3 oxide.
TL;DR: In this article, the α-Zr matrix surrounding second phase particles acts as a trapping site for hydrogen, which has not been previously reported in zirconium alloys.
Abstract: Zirconium alloys are used in safety-critical roles in the nuclear industry and their degradation due to ingress of hydrogen in service is a concern. In this work experimental evidence, supported by density functional theory modelling, shows that the α-Zr matrix surrounding second phase particles acts as a trapping site for hydrogen, which has not been previously reported in zirconium. This is unaccounted for in current models of hydrogen behaviour in Zr alloys and as such could impact development of these models. Zircaloy-2 and Zircaloy-4 samples were corroded at 350 °C in simulated pressurised water reactor coolant before being isotopically spiked with 2H2O in a second autoclave step. The distribution of 2H, Fe and Cr was characterised using nanoscale secondary ion mass spectrometry (NanoSIMS) and high-resolution energy dispersive X-ray spectroscopy. 2H- was found to be concentrated around second phase particles in the α-Zr lattice with peak hydrogen isotope ratios of 2H/1H = 0.018-0.082. DFT modelling confirms that the hydrogen thermodynamically favours sitting in the surrounding zirconium matrix rather than within the second phase particles. Knowledge of this trapping mechanism will inform the development of current understanding of zirconium alloy degradation through-life.
TL;DR: In this paper, the authors developed a new model called Hydride Nucleation-Growth-Dissolution (HNGD), which accounts for hydride nucleation and growth as two distinct precipitation components.
TL;DR: In this article, the effects of high energy heavy ion irradiation in the temperature range of 300-550°C on the structure of chromium coatings deposited on Zr-based (E110) alloy substrate by the cathodic arc evaporation method were studied.
TL;DR: In this article, a first-of-its-kind analysis to understand the impact of CRUD deposition on the CVD SiC corrosion suggests that SiC dissolution would reduce significantly as a stable CRUD layer grows on the SiC surface.
TL;DR: In this article, the effect of the temperature of the high pressure torsion (HPT) deformation and subsequent annealing in a wide temperature range on the structural and phase transformations in the Zr-2.5% Nb alloy and its microhardness has been studied.
TL;DR: In this article, a rate theory of defect removal is introduced, and suggests that the impact of the irradiation rate on damage accumulation depends on the ratio of internal sink strength to the grain boundary sink strength.
TL;DR: In this paper, the critical behavior of interfacial t-ZrO2 and other oxide features under the critical transition condition was analyzed. And the growth nature and evolution mechanism of t-zirconium alloys was further illustrated.
TL;DR: In this paper, the mechanical performance of cracked surface-coated Zircaloy cladding, which has different coating materials, coating thicknesses and initial crack lengths, has been investigated.
01 Apr 2021
TL;DR: In this paper, the sliding effect and accumulation of shear strain in Zr-1%Nb alloy at various stages of high pressure torsion (HPT) was estimated.
Abstract: The authors previously used the accumulative high-pressure torsion (ACC HPT) method for the first time on steel 316, β-Ti alloy, and bulk metallic glass vit105. On low-alloyed alloys, in particular, the zirconium alloy Zr-1%Nb, the new method was not used. This alloy has a tendency to α → ω phase transformations at using simple HPT. When using ACC HPT, the α → ω transformation can be influenced to a greater extent. This article studies the sliding effect and accumulation of shear strain in Zr-1%Nb alloy at various stages of high-pressure torsion (HPT). The degree of shear deformation at different stages of HPT was estimated. The influence of various high-pressure torsion conditions on the micro-hardness and phase composition by X-ray diffraction (XRD) of Zr-1%Nb was analyzed. It is shown that at high-pressure torsion revolutions of n = 2, anvils and the specimen significantly slip, which is a result of material strengthening. It was found that despite sliding, regular high-pressure torsion resulted in the high strengthening of Zr-1%Nb alloy (micro-hardness more than doubled), and after high-pressure torsion n = 10, up to 97% of the high-pressure ω-phase was formed in it (as in papers of other researchers). Accumulative high-pressure torsion deformation leads to the strongest transformation of the Zr-1%Nb structure and Hv and, therefore, to a higher real strain of the material due to composition by upsetting and torsion in strain cycles.
TL;DR: In this article, a phase transition temperature for all three compositions was estimated from the temperature at which an abrupt and rapid reduction in ultrasonic velocities was observed, which was attributed to a partial retention of the high temperature phase following thermal annealing.
TL;DR: In this paper, a review of the current Zr alloys and opportunities for advanced zirconium alloys to meet the demands of a structural material in fusion reactors is presented.
TL;DR: In this article, a modified thermo-gravimetric analyzer was used to investigate the oxidation characteristics of zirconium-4 and Zr-Sn-Nb alloys in steam, oxygen and air atmosphere respectively in temperature range of 650-1250℃ by a modified thermodynamic analyzer.