Low temperature neutron irradiation effects on microstructure and tensile properties of molybdenum

Li, Meimei; Eldrup, Morten Mostgaard; Byun, Thak Sang; Hashimoto, Naoyuki; Snead, Lance Lewis; Zinkle, S.J.

doi:10.1016/j.jnucmat.2007.12.001

Cited by 44 publications

(26 citation statements)

References 54 publications

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“…From the results it is possible to notice that, in general, both the materials exhibit a yielding instability, which is in accordance with the results find by other researchers (e.g. [3,7,8]). The instability is present also in compression for Mo1, while Mo2 does not show instability in compression.…”

Section: Resultssupporting

confidence: 91%

“…[3][4][5]) from low to very high temperature conditions at different the strain-rates, ranging from quasi-static up to high strainrates. In other cases [6][7][8] the tensile behavior was investigated at different temperatures, but the mechanical characterization was limited to medium-low strain-rates. In some cases, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…In some cases, e.g. [8,9], also the effect of the irradiation was investigated and modelled. Finally, considering the results reported in [10][11][12][13][14], an asymmetric behavior is expected in compression and tension tests: this was a general characteristic of BCC metals and it was previously noticed on molybdenum.…”

Section: Introductionmentioning

confidence: 99%

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Investigation and Mechanical Modelling of Pure Molybdenum at High Strain-Rate and Temperature

Scapin

Peroni

Carra

2016

J. dynamic behavior mater.

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This work shows the results obtained from the investigation of the mechanical behavior of two batches of pure molybdenum specimens (C99.97 % Mo, Mo1 supplied by Plansee and Mo2 supplied by AT&M) under static and dynamic loading conditions at different temperatures, both under tensile and compressive loading conditions. Due to its properties molybdenum has applications in several fields including nuclear. At this moment, it is a good candidate for structural material application for Beam Intercepting Devices of the Large Hadron Collider at CERN, Geneva. The experimental tests in tensile loading condition were performed on small dog-bone specimens. A series of tests at room temperature and a range of strainrates was performed in order to obtain information about the strain-rate sensitivity of the material. A series of tests at different temperatures in both static and high dynamic loading conditions was performed in order to obtain information about the thermal softening of the material. The dynamic tests were performed using the Hopkinson Bar technique, and the heating of the specimen was performed using an induction coil system. The experimental tests in compression were carried out on cylindrical specimens at room temperature and a range of strain-rates. The experimental data were analyzed via a numerical inverse method based on Finite Element numerical simulations.This approach allows to obtain the effective stress versus strain curves, which cannot be derived by using standard relations since instability and necking were present. Moreover, it also allows the non-uniform distribution of strain-rate and temperature inside the specimen to be accounted for. The results obtained from compression tests confirm the data obtained in tension in terms of strainhardening and strain-rate sensitivity, even if the material exhibits a tension-compression asymmetry of the behavior. The analysis of the hardening, temperature and strain-rate sensitivities reveals that a unique standard visco-plastic model could not be defined to reproduce the material strength behavior under different loading conditions, especially over wide range of variation of the variables of interest.Keywords Refractory metal Á High temperature Á High strain-rate Á Hopkinson bar Á Tensile and compression Á Nuclear applications Á Instability Á FE-based numerical inverse approach

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Investigation and Mechanical Modelling of Pure Molybdenum at High Strain-Rate and Temperature

Scapin

Peroni

Carra

2016

J. dynamic behavior mater.

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“…For example, TEM with in situ ion irradiation experiments was conducted on molybdenum with 1 MeV Kr ions at the IVEM-Tandem Facility in combination with rate theory modeling. The in situ ion irradiation experiments were explicitly designed to compare with neutron irradiation data of the identical material reported in a previous study [1]. A spatially-dependent cluster dynamic model was developed to explicitly simulate the damage by 1 MeV Kr ion irradiation in a Mo thin film with temporal and spatial dependence of defect distribution.…”

mentioning

confidence: 99%

TEM with in situ Ion Irradiation of Nuclear Materials: The IVEM-Tandem User Facility

Kirk

Baldo

et al. 2015

Microsc Microanal

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The IVEM-Tandem User Facility at the Argonne National Laboratory (ANL) is a world-leading research facility for in situ TEM study of ion irradiation damage and ion implantation near the atomic resolution. The IVEM-Tandem Facility interfaces a 500 kV ion implanter to a 300 kV Hitachi H-9000NAR transmission electron microscope. This combination allows experiments conducted with simultaneous ion irradiation/implantation and electron microscopy at temperatures ranging from 20 -1300 K. With superior electron brightness of a LaB6 filament, the H-9000 microscope is ideally suited for imaging irradiation-induced defects using diffraction contrast, a well-established technique in most cases superior to other imaging techniques. This permits effective real time observation of nanoscale defect formation and evolution during irradiation. Coupled with well-controlled irradiation conditions (constant specimen orientation and area, specimen temperature, ion type, ion energy, dose rate, dose, and applied strain), it provides key information on structure and defect dynamics of a material in an irradiation environment.The IVEM-Tandem Facility was commissioned in 1995 in the Materials Science Division of ANL, and was part of Argonne's Electron Microscopy Center, a National User Facility supported by the Department of Energy (DOE) Office of Science, Basic Energy Science. It was recently transitioned to the Nuclear Engineering Division of ANL, currently supported by the DOE Office of Nuclear Energy. The IVEM-Tandem serves more than 20 active user groups from universities, national laboratories, and nuclear industry in the U.S. and abroad, conducting research in areas of advanced alloys, accident tolerant materials and fuels, radiation-resistant fuel cladding, storage materials for spent fuels, and validation and verification of computer modeling and simulations. A facility upgrade is being considered to best address the critical problems of fission and fusion energy materials.TEM with in situ ion irradiation has made tremendous contributions to the understanding of defect production, accumulation and evolution under irradiation. Many of fundamental questions of radiation damage, e.g. single cascades, cascade -cascade, or cascade -subcascade interactions, defect production and annihilation rates of visible defect clusters, defect and dislocation interactions, etc. have been answered. A recent new direction is to predict neutron damage in bulk through in situ ion irradiation studies of thin films and coordinated computer modeling so that neutron irradiation effects can be evaluate by easily controlled ion irradiation experiments. For example, TEM with in situ ion irradiation experiments was conducted on molybdenum with 1 MeV Kr ions at the IVEM-Tandem Facility in combination with rate theory modeling. The in situ ion irradiation experiments were explicitly designed to compare with neutron irradiation data of the identical material reported in a previous study [1]. A spatially-dependent cluster dynamic model was developed to explicitly...

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“…The essential objectives of this experiment are to measure and characterize the formation of defect microstructure as functions of these parameters (all of which can be modeled by computer simulation), compare to neutron irradiation data on the same material [1], and demonstrate the methods of extrapolation from ion irradiations at high dose rate in thin samples, to neutron irradiation at low dose rate in bulk samples. Ideally, if successful, an ion irradiation and electron microscopy of a material in our facility over a day or two can result, through modeling, in predictions of microstructural behavior and property changes over several years, even decades, of neutron irradiation in fission or fusion reactors.…”

mentioning

confidence: 99%

Damage Correlation between in situ Ion Irradiation and Neutron Irradiation in Molybdenum

Kirk

Baldo

2009

Microsc Microanal

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It has long been hoped that computer modeling can accurately predict responses in materials over many years of neutron irradiation at elevated temperatures. Although much progress has been achieved in the development of the modeling techniques, experiments involving neutron irradiation to confirm model predictions are relatively few and usually quite difficult with a long turnaround time. To solve this experimental difficulty, we are pursuing a new direction to utilize the IVEMTandem Facility at ANL to benchmark computer models for irradiation of materials.In this new effort, we recently employed 1 MeV Kr ion irradiation in situ in our TEM facility to produce and image defect clusters (generally dislocation loops) at controlled temperatures, over a range of doses and dose rates, and over a range of sample thicknesses in well characterized molybdenum thin foils. The essential objectives of this experiment are to measure and characterize the formation of defect microstructure as functions of these parameters (all of which can be modeled by computer simulation), compare to neutron irradiation data on the same material [1], and demonstrate the methods of extrapolation from ion irradiations at high dose rate in thin samples, to neutron irradiation at low dose rate in bulk samples. Ideally, if successful, an ion irradiation and electron microscopy of a material in our facility over a day or two can result, through modeling, in predictions of microstructural behavior and property changes over several years, even decades, of neutron irradiation in fission or fusion reactors.Data consisting of defect cluster densities were obtained in pure Mo foils irradiated in situ to a series of doses and imaged using weak-beam dark-field with a constant diffraction condition, such that defect areal density could be measured as a function of thickness over the wedged foil. Separate experiments were performed at three temperatures, 20 and 80°C, which are just below stage three where only interstitials have high mobility, and 300°C, which is just above stage three where both interstitials and vacancies are highly mobile. In addition, data was obtained at three dose rates at 80°C.An example of the image results is shown in Figure 1. An example of quantitative results in Figure 2 demonstrates the different dependencies of defect cluster density on dose and foil thickness at 80 and 300°C. A next step in this experimental program is to obtain tomographic data to measure defect density as a function of foil depth and thus quantify the effects of nearby surfaces on point defect clustering. Finally, we hope to make a detailed comparison with computer simulations [2] constructed to match our various experimental conditions and extensive data on defect cluster density as functions of sample thickness, ion dose and dose rate, and irradiation temperature.

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Low temperature neutron irradiation effects on microstructure and tensile properties of molybdenum

Cited by 44 publications

References 54 publications

Investigation and Mechanical Modelling of Pure Molybdenum at High Strain-Rate and Temperature

Investigation and Mechanical Modelling of Pure Molybdenum at High Strain-Rate and Temperature

TEM with in situ Ion Irradiation of Nuclear Materials: The IVEM-Tandem User Facility

Damage Correlation between in situ Ion Irradiation and Neutron Irradiation in Molybdenum

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