Irradiation-Induced Growth and Microstructure of Recrystallized, Cold Worked and Quenched Zircaloy-2, NSF, and E635 Alloys PDF Download
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Author: D. W. White
Publisher:
ISBN:
Category : Irradiation-induced growth
Languages : en
Pages : 19
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Book Description
This paper is devoted to the study of the effect of the texture, phase composition, and microstructure on the irradiation-induced growth strain (GS) of zirconium-based alloys. GS measurements and TEM microstructural examinations were performed on Zry-2, NSF, and E635 samples in the recrystallized, beta quenched and cold-worked (CW) conditions. The samples were irradiated in the BOR-60 reactor in the temperature range of 315-325°C up to a neutron fluence level of 1.1 x 1026 n/m2 (E>1MeV), i.e., up to a damage dose of 23 dpa. Growth strains of NSF and E635 alloys in all states and in the longitudinal and transverse directions are lower as compared to those of Zry-2, and do not exceed 0.2 % even at the maximum fluence level. As for recrystallized Zry-2, the GS kinetics are characterized by the appearance of the accelerated growth stage. A combination of a certain amount of Nb, Fe, and Sn in the matrix content plays a key role in GS kinetics. The higher the degree of CW, the higher the irradiation growth but its rate of increase with increasing fluence is different for alloys of different compositions. The maximum GS, reaching 0.72 %, is observed in the 20 % CW Zry-2 samples. Texture, along with the alloy composition, is one of the main GS-determining factors. Irradiation growth of the transversal samples is lower as compared to the longitudinal ones because of texture. As for quenched alloys, the texture is practically isotropic and GS values are low, independent of the alloy composition. In CW materials, the density of ‹c›- dislocations greatly affects the irradiation growth strain. Particles of Zr(Fe,Cr)2 and Zr2(Fe,Ni) phases in Zry-2 as well as Zr(Nb,Fe)2 in NSF and E635 are depleted in iron under irradiation. The Fe goes into the matrix and modifies its properties. The HCP lattice structure in the Laves phases in NSF and E635 changes into BCC (?-Nb-type). FCC (Zr,Nb)2Fe precipitates preserve on the whole their composition and structure; no amorphization of the Nb-containing precipitates is observed. The Zr2(Fe,Ni) precipitates with a BCT lattice remain crystalline, and HCP Zr(Cr,Fe)2 precipitates undergo amorphization. The average particle size in the irradiated alloys is larger and the concentration is a little lower as compared to the unirradiated ones. Irradiation-induced fine dispersed precipitates about 3 nm in size, probably enriched in niobium, appear in NSF and E635. The observed changes of microhardness are discussed from the viewpoint of generation of radiation defects (clusters, dislocation loops), evolution of the initial dislocation structure, and matrix composition (enrichment in Fe, Cr, and, probably, Nb).
Author: D. W. White
Publisher:
ISBN:
Category : Irradiation-induced growth
Languages : en
Pages : 19
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Book Description
This paper is devoted to the study of the effect of the texture, phase composition, and microstructure on the irradiation-induced growth strain (GS) of zirconium-based alloys. GS measurements and TEM microstructural examinations were performed on Zry-2, NSF, and E635 samples in the recrystallized, beta quenched and cold-worked (CW) conditions. The samples were irradiated in the BOR-60 reactor in the temperature range of 315-325°C up to a neutron fluence level of 1.1 x 1026 n/m2 (E>1MeV), i.e., up to a damage dose of 23 dpa. Growth strains of NSF and E635 alloys in all states and in the longitudinal and transverse directions are lower as compared to those of Zry-2, and do not exceed 0.2 % even at the maximum fluence level. As for recrystallized Zry-2, the GS kinetics are characterized by the appearance of the accelerated growth stage. A combination of a certain amount of Nb, Fe, and Sn in the matrix content plays a key role in GS kinetics. The higher the degree of CW, the higher the irradiation growth but its rate of increase with increasing fluence is different for alloys of different compositions. The maximum GS, reaching 0.72 %, is observed in the 20 % CW Zry-2 samples. Texture, along with the alloy composition, is one of the main GS-determining factors. Irradiation growth of the transversal samples is lower as compared to the longitudinal ones because of texture. As for quenched alloys, the texture is practically isotropic and GS values are low, independent of the alloy composition. In CW materials, the density of ‹c›- dislocations greatly affects the irradiation growth strain. Particles of Zr(Fe,Cr)2 and Zr2(Fe,Ni) phases in Zry-2 as well as Zr(Nb,Fe)2 in NSF and E635 are depleted in iron under irradiation. The Fe goes into the matrix and modifies its properties. The HCP lattice structure in the Laves phases in NSF and E635 changes into BCC (?-Nb-type). FCC (Zr,Nb)2Fe precipitates preserve on the whole their composition and structure; no amorphization of the Nb-containing precipitates is observed. The Zr2(Fe,Ni) precipitates with a BCT lattice remain crystalline, and HCP Zr(Cr,Fe)2 precipitates undergo amorphization. The average particle size in the irradiated alloys is larger and the concentration is a little lower as compared to the unirradiated ones. Irradiation-induced fine dispersed precipitates about 3 nm in size, probably enriched in niobium, appear in NSF and E635. The observed changes of microhardness are discussed from the viewpoint of generation of radiation defects (clusters, dislocation loops), evolution of the initial dislocation structure, and matrix composition (enrichment in Fe, Cr, and, probably, Nb).
Author:
Publisher: Elsevier
ISBN: 0081028660
Category : Science
Languages : en
Pages : 4871
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Book Description
Materials in a nuclear environment are exposed to extreme conditions of radiation, temperature and/or corrosion, and in many cases the combination of these makes the material behavior very different from conventional materials. This is evident for the four major technological challenges the nuclear technology domain is facing currently: (i) long-term operation of existing Generation II nuclear power plants, (ii) the design of the next generation reactors (Generation IV), (iii) the construction of the ITER fusion reactor in Cadarache (France), (iv) and the intermediate and final disposal of nuclear waste. In order to address these challenges, engineers and designers need to know the properties of a wide variety of materials under these conditions and to understand the underlying processes affecting changes in their behavior, in order to assess their performance and to determine the limits of operation. Comprehensive Nuclear Materials, Second Edition, Seven Volume Set provides broad ranging, validated summaries of all the major topics in the field of nuclear material research for fission as well as fusion reactor systems. Attention is given to the fundamental scientific aspects of nuclear materials: fuel and structural materials for fission reactors, waste materials, and materials for fusion reactors. The articles are written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource of information. Most of the chapters from the first Edition have been revised and updated and a significant number of new topics are covered in completely new material. During the ten years between the two editions, the challenge for applications of nuclear materials has been significantly impacted by world events, public awareness, and technological innovation. Materials play a key role as enablers of new technologies, and we trust that this new edition of Comprehensive Nuclear Materials has captured the key recent developments. Critically reviews the major classes and functions of materials, supporting the selection, assessment, validation and engineering of materials in extreme nuclear environments Comprehensive resource for up-to-date and authoritative information which is not always available elsewhere, even in journals Provides an in-depth treatment of materials modeling and simulation, with a specific focus on nuclear issues Serves as an excellent entry point for students and researchers new to the field
Author: Robert Odette
Publisher: Newnes
ISBN: 012397349X
Category : Technology & Engineering
Languages : en
Pages : 673
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Book Description
High-performance alloys that can withstand operation in hazardous nuclear environments are critical to presentday in-service reactor support and maintenance and are foundational for reactor concepts of the future. With commercial nuclear energy vendors and operators facing the retirement of staff during the coming decades, much of the scholarly knowledge of nuclear materials pursuant to appropriate, impactful, and safe usage is at risk. Led by the multi-award winning editorial team of G. Robert Odette (UCSB) and Steven J. Zinkle (UTK/ORNL) and with contributions from leaders of each alloy discipline, Structural Alloys for Nuclear Energy Applications aids the next generation of researchers and industry staff developing and maintaining steels, nickel-base alloys, zirconium alloys, and other structural alloys in nuclear energy applications. This authoritative reference is a critical acquisition for institutions and individuals seeking state-of-the-art knowledge aided by the editors’ unique personal insight from decades of frontline research, engineering and management. Focuses on in-service irradiation, thermal, mechanical, and chemical performance capabilities. Covers the use of steels and other structural alloys in current fission technology, leading edge Generation-IV fission reactors, and future fusion power reactors. Provides a critical and comprehensive review of the state-of-the-art experimental knowledge base of reactor materials, for applications ranging from engineering safety and lifetime assessments to supporting the development of advanced computational models.
Author: Spencer Harrison Bush
Publisher:
ISBN:
Category : Annealing of metals
Languages : en
Pages : 134
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Book Description
Author: RB. Adamson
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 23
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Book Description
Irradiation growth behavior of zirconium, Zircaloy-2 and Zircaloy-4,Zr-2.5Nb, and Zr-3.5Sn-0.8Mo-0.8Nb (EXCEL) was studied on specimens irradiated in the Experimental Breeder Reactor II (EBR-II) to fluences of 1.2 to 16.9 x 1025 neutrons (n).m-2 (E > 1 MeV) in the temperature range 644 to 725 K. In Zircaloy, growth and growth rate were observed to increase continuously with fluence up to 16.9 x 1025 n.m-2 with no indication of saturation in either recrystallized or cold-worked materials. Positive growth strains of 1.5% and negative strains of approximately 2% to 2.5% were observed in both recrystallized and cold-worked Zircaloy. The formation of both a-type loops and c component dislocations is recrystallized Zircaloy under irradiation appears to be the basis in this material for growth strains similar in magnitude to those in cold-worked Zircaloy. Alloy additions to zirconium can increase growth by as much as an order of magnitude for a given texture at the higher irradiation temperatures and fluences. A sharp change to increasing growth rate with temperature occurs in Zircaloy at ~670 K, with a similar trend indicated for the other alloys. Although growth in all these alloys is a strong function of crystallographic texture, an exact (1-3f) type of dependence is not always apparent. In Zr-2.5Nb the dependence of growth on texture appears to be masked by the precipitation of betaniobium, with a transition to a well-defined texture dependence being a function of fluence and temperature. Significant differences in growth behavior were observed in nominally similar Zircaloys, apparently due to minor microstructural or chemical differences.
Author: AV. Tselischev
Publisher:
ISBN:
Category : Composition
Languages : en
Pages : 22
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Book Description
The studies of the dislocation structure, phase, and microchemical compositions of alloy Zr-1Nb-1.2Sn-0.35Fe (E635) and its modifications containing Fe from 0.15 to 0.65% were carried out before and after research reactor irradiation at ~350°C to maximal fluence of ~1027 m-2 (E > 0.1 MeV) and at ~60°C. The size and concentration of the a-type loops depend on the alloy composition and fluence and saturate even at low doses (1 dpa). The evolution of the c-component dislocation structure in recrystallized alloys of E365 type is determined by the chemical and phase compositions of alloys specifically, by the Fe/Nb ratio and the threshold dose, and is consistent with the irradiation growth strain acceleration. In E635 alloy containing 0.15%Fe the accelerated growth is observed after the dose of 15 dpa and is attended with the evolution of the c dislocation structure which is similar to Zr-1Nb (E110) alloy behavior. The irradiation induced growth of E635 type alloy containing 0.65% Fe is similar to that of E635 having the normal composition; no
Author: RB. Adamson
Publisher:
ISBN:
Category : Heat treatment
Languages : en
Pages : 18
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Book Description
Data on irradiation growth of Zircaloy is presented. Irradiation growth is defined as irradiation-induced changes in dimensions in the absence of an applied stress. It is shown that the primary variables are fluence, irradiation temperature, amount of prior cold work, heat treatment, and texture. For recrystallized Zircaloy: growth (a) increases as f, the fraction of basal poles in measurement direction, decreases; shrinkage is possible for large f-factors, (b) increases with increasing temperature up to about 300°C, above which it decreases, (c) tends towards saturation for fluences greater than about 1 x 1021 neutrons (n)/cm2(E> 1 MeV). For cold worked/ stress relieved material: growth (a) increases linearly with fluence up to at least 3 x 1021 n/cm2, and (b) increases linearly with increase in the amount of cold work. For recrystallized material, all irradiation growth is recovered during suitable thermal anneals, while for cold worked material only a portion of the growth is recoverable. Rapid recovery occurs above 350°C (644°F) with an activation energy of 1.67 eV. Mechanistic implications of the gathered data are discussed.
Author: RA. Holt
Publisher:
ISBN:
Category : Congress
Languages : en
Pages : 15
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Book Description
Accelerating irradiation growth has been reported for several zirconium alloys with a range of metallurgical states during high-temperature tests in fast-breeder reactors (673 to 723 K) for annealed Zircaloys in thermal test reactors at power reactor temperatures (523 to 623 K) and in power reactor core components fabricated from annealed or recrystallized Zircaloy. In the latter case, there was a transition from low to high irradiation growth rates at moderate fluences (about 3 x 1025 n/m2, E > 1 MeV, at 580 K) related to the nucleation and growth of basal plane c-component loops.
Author: S. H. Bush
Publisher:
ISBN:
Category : Annealing of metals
Languages : en
Pages : 96
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Reactor-grade Zircaloy-2 and vacuum-melted Zircaloy3V were prepared by arc melting twice under vacuum. In addition, argon-melted Zircaloy-3A was prepared by arc melting in a vacuum and then under Ar. The materials were rolled into plate. Specimens of the same thickness and having the same penultimate grain size were prepared at cold work levels of 10, 25, and 50%. The specimens were annealed at 300, 400, 500, 600, 700, and 800 un. Concent 85% C at He, and vacuum (10/sup -4/ to 10/sup -5/ mm Hg) atmospheres. Recovery, recrystallization, and grain growth as a function of cold work level, composition, annealing time, temperature, and atmosphere were studied by hardness and electric resistivity measurements, and by metallographic observations. Recovery and secondary hardening were observed at temperatures of 300 to 500 un. Concent 85% C. Recrystallization began at 500 un. Concent 85% C and was essentially complete at 600 un. Concent 85% C after 1000 min or less. Recrystallization occurred by subgrain growth in material cold worked 10%. Conventional nucleation and growth occurred at 25 and 50% cold work. Definite differences in response to annealing atmosphere were observed. Vacuum-annealed alloys recrystallized more slowly than air- or He-annealed alloys. (auth).
