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Y Zayachuk - One of the best experts on this subject based on the ideXlab platform.
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the effect of ion flux on plasma induced modification and deuterium retention in tungsten and tungsten Tantalum Alloys
Journal of Nuclear Materials, 2015Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, A Manhard, W Jacob, G Van OostAbstract:The paper presents the results of an experimental study of deuterium retention in W and W–Ta alloy that were exposed to first-wall relevant low flux (10 20 m 2 s 1 ) deuterium plasma in the ECR plasma generator PlaQ. Subsequent analysis included surface imaging by optical microscopy, deuterium depth profiling by nuclear reaction analysis (NRA) and measurements of deuterium content by thermal desorption spectroscopy (TDS). It was found that under investigated exposure conditions the deuterium content was higher in W–Ta alloy than in W. Combined with the previously reported results showing that under high-flux (10 24 m 2 s 1 ) retention is higher in W instead, this gives rise to a peculiar flux effect – dependence of relative retention between different materials on exposure flux. We interpret this effect as evidence that at different flux ranges different populations of trapping sites determine the retention, namely pre-existing microstructural traps at low-flux exposure and plasma-induced ones at high-flux exposure.
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depth profiling of the modification induced by high flux deuterium plasma in tungsten and tungsten Tantalum Alloys
Nuclear Fusion, 2014Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, A Manhard, W Jacob, G Van OostAbstract:The present work reports the results of an experimental study of the depth distribution and fluence dependence of deuterium plasma-induced material modification of tungsten and tungsten‐Tantalum Alloys. Plasma-induced damage was created by exposure to high-flux deuterium plasma in the plasma generator Pilot-PSI, followed by the degassing and subsequent decoration of created defects with deuterium by another plasma exposure. The depth distribution of deuterium from the decorating exposure reflects the distribution of plasma-induced defects. Depth profiling of this decorating deuterium, was performed by nuclear reaction analysis. It was found that plasma-induced material modification, which manifested itself as an increase of the deuterium concentration in the samples pre-exposed with high-flux plasma in comparison to the samples without such pre-exposure extends down to more than 5 µm from the surface. This increase features a tendency to saturation with increasing fluence of the damaging high-flux plasma. Over the entire probing range, with the exception of the narrow surface region and the deep region beyond 5 µm, the deuterium content is lower in pre-exposed W‐Ta than in similarly pre-exposed W. Sub-surface features formed as a result of high-flux plasma exposure were studied with the help of focused ion beam cross-sectioning. W was found to contain plasma-induced cavities down to much larger depth than W‐Ta.
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Depth profiling of the modification induced by high-flux deuterium plasma in tungsten and tungsten?Tantalum Alloys
Nuclear Fusion, 2014Co-Authors: Y Zayachuk, M H J T Hoen, A Manhard, W Jacob, P.a. Zeijlmans Van Emmichoven, G. Van OostAbstract:The present work reports the results of an experimental study of the depth distribution and fluence dependence of deuterium plasma-induced material modification of tungsten and tungsten‐Tantalum Alloys. Plasma-induced damage was created by exposure to high-flux deuterium plasma in the plasma generator Pilot-PSI, followed by the degassing and subsequent decoration of created defects with deuterium by another plasma exposure. The depth distribution of deuterium from the decorating exposure reflects the distribution of plasma-induced defects. Depth profiling of this decorating deuterium, was performed by nuclear reaction analysis. It was found that plasma-induced material modification, which manifested itself as an increase of the deuterium concentration in the samples pre-exposed with high-flux plasma in comparison to the samples without such pre-exposure extends down to more than 5 µm from the surface. This increase features a tendency to saturation with increasing fluence of the damaging high-flux plasma. Over the entire probing range, with the exception of the narrow surface region and the deep region beyond 5 µm, the deuterium content is lower in pre-exposed W‐Ta than in similarly pre-exposed W. Sub-surface features formed as a result of high-flux plasma exposure were studied with the help of focused ion beam cross-sectioning. W was found to contain plasma-induced cavities down to much larger depth than W‐Ta.
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surface modification of tungsten and tungsten Tantalum Alloys exposed to high flux deuterium plasma and its impact on deuterium retention
Nuclear Fusion, 2013Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, I Uytdenhouwen, D Terentyev, G Van OostAbstract:Samples of tungsten and tungsten-Tantalum alloy (with 5 mass per cent of Ta) were exposed to high-flux deuterium plasma at different fluences. The surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS). In the high fluence range of similar to 3.5 x 10(26)-10(27)m(-2), multiple large-size blisters are formed on the W surface, while blisters on the W-Ta surface are considerably smaller in size and number. Deuterium retention in this fluence range was found to be systematically higher in W than in W-Ta. Correlation between the evolution of the blistering patterns and the TDS spectra as a function of fluence suggests that trapping in the sub-surface cavities associated with blisters is the predominant trapping mechanism in tungsten in the case of high fluence exposures. We attribute the lower retention in W-Ta under the investigated conditions to the weaker blistering.
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Surface modification of tungsten and tungsten–Tantalum Alloys exposed to high-flux deuterium plasma and its impact on deuterium retention
Nuclear Fusion, 2013Co-Authors: Y Zayachuk, M H J T Hoen, I Uytdenhouwen, P.a. Zeijlmans Van Emmichoven, D Terentyev, G. Van OostAbstract:Samples of tungsten and tungsten-Tantalum alloy (with 5 mass per cent of Ta) were exposed to high-flux deuterium plasma at different fluences. The surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS). In the high fluence range of similar to 3.5 x 10(26)-10(27)m(-2), multiple large-size blisters are formed on the W surface, while blisters on the W-Ta surface are considerably smaller in size and number. Deuterium retention in this fluence range was found to be systematically higher in W than in W-Ta. Correlation between the evolution of the blistering patterns and the TDS spectra as a function of fluence suggests that trapping in the sub-surface cavities associated with blisters is the predominant trapping mechanism in tungsten in the case of high fluence exposures. We attribute the lower retention in W-Ta under the investigated conditions to the weaker blistering.
Yusheng Shi - One of the best experts on this subject based on the ideXlab platform.
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improvement on mechanical properties and corrosion resistance of titanium Tantalum Alloys in situ fabricated via selective laser melting
Journal of Alloys and Compounds, 2019Co-Authors: Danlei Zhao, Changjun Han, Kun Zhou, Qingsong Wei, Jie Liu, Yusheng ShiAbstract:Abstract In this study, the role of Tantalum (Ta) on the phase transformation, microstructure evolution, mechanical properties and corrosion resistance of titanium-Tantalum (Ti–Ta) Alloys in-situ fabricated via selective laser melting (SLM) was investigated. Ti–Ta mixed powders with different Ta ratios ranging from 0 to 25 wt % were prepared by ball milling for the SLM process. With the increase of Ta content, the SLM-processed Ti–Ta Alloys exhibits the microstructure evolution from the lath α grain to acicular α' + primary cellular β grains, accompanying with the gradual suppression of martensite transformation. The β-stabilized effect of Ta promotes the formation of β (Ti, Ta) solid solution phase in the Alloys. The rise of Ta addition in SLM-processed Ti–Ta Alloys contributes to the improvement on the tensile strength from 641 to 1186 MPa and the microhardness from 257 to 353 HV, which results from a combined effect of grain refinement strengthening and the solid solution strengthening. The Young's modulus decreases from 115 to 89 GPa due to the increasing amount of β phase. Additionally, the corrosion resistance of the Ti–Ta Alloys is enhanced with few pits on the surfaces due to the increasing amount of Ta2O5 identified through X-ray photoelectron spectroscopy. These findings provide the knowledge and boost the further understanding on the SLM-processed Ti–Ta Alloys as promising candidates for biomedical application.
G Van Oost - One of the best experts on this subject based on the ideXlab platform.
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the effect of ion flux on plasma induced modification and deuterium retention in tungsten and tungsten Tantalum Alloys
Journal of Nuclear Materials, 2015Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, A Manhard, W Jacob, G Van OostAbstract:The paper presents the results of an experimental study of deuterium retention in W and W–Ta alloy that were exposed to first-wall relevant low flux (10 20 m 2 s 1 ) deuterium plasma in the ECR plasma generator PlaQ. Subsequent analysis included surface imaging by optical microscopy, deuterium depth profiling by nuclear reaction analysis (NRA) and measurements of deuterium content by thermal desorption spectroscopy (TDS). It was found that under investigated exposure conditions the deuterium content was higher in W–Ta alloy than in W. Combined with the previously reported results showing that under high-flux (10 24 m 2 s 1 ) retention is higher in W instead, this gives rise to a peculiar flux effect – dependence of relative retention between different materials on exposure flux. We interpret this effect as evidence that at different flux ranges different populations of trapping sites determine the retention, namely pre-existing microstructural traps at low-flux exposure and plasma-induced ones at high-flux exposure.
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depth profiling of the modification induced by high flux deuterium plasma in tungsten and tungsten Tantalum Alloys
Nuclear Fusion, 2014Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, A Manhard, W Jacob, G Van OostAbstract:The present work reports the results of an experimental study of the depth distribution and fluence dependence of deuterium plasma-induced material modification of tungsten and tungsten‐Tantalum Alloys. Plasma-induced damage was created by exposure to high-flux deuterium plasma in the plasma generator Pilot-PSI, followed by the degassing and subsequent decoration of created defects with deuterium by another plasma exposure. The depth distribution of deuterium from the decorating exposure reflects the distribution of plasma-induced defects. Depth profiling of this decorating deuterium, was performed by nuclear reaction analysis. It was found that plasma-induced material modification, which manifested itself as an increase of the deuterium concentration in the samples pre-exposed with high-flux plasma in comparison to the samples without such pre-exposure extends down to more than 5 µm from the surface. This increase features a tendency to saturation with increasing fluence of the damaging high-flux plasma. Over the entire probing range, with the exception of the narrow surface region and the deep region beyond 5 µm, the deuterium content is lower in pre-exposed W‐Ta than in similarly pre-exposed W. Sub-surface features formed as a result of high-flux plasma exposure were studied with the help of focused ion beam cross-sectioning. W was found to contain plasma-induced cavities down to much larger depth than W‐Ta.
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surface modification of tungsten and tungsten Tantalum Alloys exposed to high flux deuterium plasma and its impact on deuterium retention
Nuclear Fusion, 2013Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, I Uytdenhouwen, D Terentyev, G Van OostAbstract:Samples of tungsten and tungsten-Tantalum alloy (with 5 mass per cent of Ta) were exposed to high-flux deuterium plasma at different fluences. The surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS). In the high fluence range of similar to 3.5 x 10(26)-10(27)m(-2), multiple large-size blisters are formed on the W surface, while blisters on the W-Ta surface are considerably smaller in size and number. Deuterium retention in this fluence range was found to be systematically higher in W than in W-Ta. Correlation between the evolution of the blistering patterns and the TDS spectra as a function of fluence suggests that trapping in the sub-surface cavities associated with blisters is the predominant trapping mechanism in tungsten in the case of high fluence exposures. We attribute the lower retention in W-Ta under the investigated conditions to the weaker blistering.
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deuterium retention in tungsten and tungsten Tantalum Alloys exposed to high flux deuterium plasmas
Nuclear Fusion, 2012Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, I Uytdenhouwen, G Van OostAbstract:A direct comparison of deuterium retention in samples of tungsten and two grades of tungsten-Tantalum Alloys-W-1% Ta and W-5% Ta, exposed to deuterium plasmas (ion flux similar to 10(24) m(-2) s(-1), ion energy at the biased target similar to 50 eV) at the plasma generator Pilot-PSI was performed using thermal desorption spectroscopy (TDS). No systematic difference in terms of total retention in tungsten and tungsten-Tantalum was identified. The measured retention value for each grade did not deviate by more than 24% from the value averaged over the three grades exposed to the same conditions. No additional desorption peaks appeared in the TDS spectra of the W-Ta samples as compared with the W target, indicating that no additional kinds of traps are introduced by the alloying of W with Ta. In the course of the experiment the same samples were exposed to the same plasma conditions several times, and it is demonstrated that samples with the history of prior exposures yield an increase in deuterium retention of up to 130% under the investigated conditions compared with the samples that were not exposed before. We consider this as evidence that exposure of the considered materials to ions with energy below the displacement threshold generates additional traps for deuterium. The positions of the release peaks caused by these traps are similar for W and W-Ta, which indicates that the corresponding traps are of the same kind.
Danlei Zhao - One of the best experts on this subject based on the ideXlab platform.
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improvement on mechanical properties and corrosion resistance of titanium Tantalum Alloys in situ fabricated via selective laser melting
Journal of Alloys and Compounds, 2019Co-Authors: Danlei Zhao, Changjun Han, Kun Zhou, Qingsong Wei, Jie Liu, Yusheng ShiAbstract:Abstract In this study, the role of Tantalum (Ta) on the phase transformation, microstructure evolution, mechanical properties and corrosion resistance of titanium-Tantalum (Ti–Ta) Alloys in-situ fabricated via selective laser melting (SLM) was investigated. Ti–Ta mixed powders with different Ta ratios ranging from 0 to 25 wt % were prepared by ball milling for the SLM process. With the increase of Ta content, the SLM-processed Ti–Ta Alloys exhibits the microstructure evolution from the lath α grain to acicular α' + primary cellular β grains, accompanying with the gradual suppression of martensite transformation. The β-stabilized effect of Ta promotes the formation of β (Ti, Ta) solid solution phase in the Alloys. The rise of Ta addition in SLM-processed Ti–Ta Alloys contributes to the improvement on the tensile strength from 641 to 1186 MPa and the microhardness from 257 to 353 HV, which results from a combined effect of grain refinement strengthening and the solid solution strengthening. The Young's modulus decreases from 115 to 89 GPa due to the increasing amount of β phase. Additionally, the corrosion resistance of the Ti–Ta Alloys is enhanced with few pits on the surfaces due to the increasing amount of Ta2O5 identified through X-ray photoelectron spectroscopy. These findings provide the knowledge and boost the further understanding on the SLM-processed Ti–Ta Alloys as promising candidates for biomedical application.
M H J T Hoen - One of the best experts on this subject based on the ideXlab platform.
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the effect of ion flux on plasma induced modification and deuterium retention in tungsten and tungsten Tantalum Alloys
Journal of Nuclear Materials, 2015Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, A Manhard, W Jacob, G Van OostAbstract:The paper presents the results of an experimental study of deuterium retention in W and W–Ta alloy that were exposed to first-wall relevant low flux (10 20 m 2 s 1 ) deuterium plasma in the ECR plasma generator PlaQ. Subsequent analysis included surface imaging by optical microscopy, deuterium depth profiling by nuclear reaction analysis (NRA) and measurements of deuterium content by thermal desorption spectroscopy (TDS). It was found that under investigated exposure conditions the deuterium content was higher in W–Ta alloy than in W. Combined with the previously reported results showing that under high-flux (10 24 m 2 s 1 ) retention is higher in W instead, this gives rise to a peculiar flux effect – dependence of relative retention between different materials on exposure flux. We interpret this effect as evidence that at different flux ranges different populations of trapping sites determine the retention, namely pre-existing microstructural traps at low-flux exposure and plasma-induced ones at high-flux exposure.
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depth profiling of the modification induced by high flux deuterium plasma in tungsten and tungsten Tantalum Alloys
Nuclear Fusion, 2014Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, A Manhard, W Jacob, G Van OostAbstract:The present work reports the results of an experimental study of the depth distribution and fluence dependence of deuterium plasma-induced material modification of tungsten and tungsten‐Tantalum Alloys. Plasma-induced damage was created by exposure to high-flux deuterium plasma in the plasma generator Pilot-PSI, followed by the degassing and subsequent decoration of created defects with deuterium by another plasma exposure. The depth distribution of deuterium from the decorating exposure reflects the distribution of plasma-induced defects. Depth profiling of this decorating deuterium, was performed by nuclear reaction analysis. It was found that plasma-induced material modification, which manifested itself as an increase of the deuterium concentration in the samples pre-exposed with high-flux plasma in comparison to the samples without such pre-exposure extends down to more than 5 µm from the surface. This increase features a tendency to saturation with increasing fluence of the damaging high-flux plasma. Over the entire probing range, with the exception of the narrow surface region and the deep region beyond 5 µm, the deuterium content is lower in pre-exposed W‐Ta than in similarly pre-exposed W. Sub-surface features formed as a result of high-flux plasma exposure were studied with the help of focused ion beam cross-sectioning. W was found to contain plasma-induced cavities down to much larger depth than W‐Ta.
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Depth profiling of the modification induced by high-flux deuterium plasma in tungsten and tungsten?Tantalum Alloys
Nuclear Fusion, 2014Co-Authors: Y Zayachuk, M H J T Hoen, A Manhard, W Jacob, P.a. Zeijlmans Van Emmichoven, G. Van OostAbstract:The present work reports the results of an experimental study of the depth distribution and fluence dependence of deuterium plasma-induced material modification of tungsten and tungsten‐Tantalum Alloys. Plasma-induced damage was created by exposure to high-flux deuterium plasma in the plasma generator Pilot-PSI, followed by the degassing and subsequent decoration of created defects with deuterium by another plasma exposure. The depth distribution of deuterium from the decorating exposure reflects the distribution of plasma-induced defects. Depth profiling of this decorating deuterium, was performed by nuclear reaction analysis. It was found that plasma-induced material modification, which manifested itself as an increase of the deuterium concentration in the samples pre-exposed with high-flux plasma in comparison to the samples without such pre-exposure extends down to more than 5 µm from the surface. This increase features a tendency to saturation with increasing fluence of the damaging high-flux plasma. Over the entire probing range, with the exception of the narrow surface region and the deep region beyond 5 µm, the deuterium content is lower in pre-exposed W‐Ta than in similarly pre-exposed W. Sub-surface features formed as a result of high-flux plasma exposure were studied with the help of focused ion beam cross-sectioning. W was found to contain plasma-induced cavities down to much larger depth than W‐Ta.
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surface modification of tungsten and tungsten Tantalum Alloys exposed to high flux deuterium plasma and its impact on deuterium retention
Nuclear Fusion, 2013Co-Authors: Y Zayachuk, M H J T Hoen, P Zeijlmans A Van Emmichoven, I Uytdenhouwen, D Terentyev, G Van OostAbstract:Samples of tungsten and tungsten-Tantalum alloy (with 5 mass per cent of Ta) were exposed to high-flux deuterium plasma at different fluences. The surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS). In the high fluence range of similar to 3.5 x 10(26)-10(27)m(-2), multiple large-size blisters are formed on the W surface, while blisters on the W-Ta surface are considerably smaller in size and number. Deuterium retention in this fluence range was found to be systematically higher in W than in W-Ta. Correlation between the evolution of the blistering patterns and the TDS spectra as a function of fluence suggests that trapping in the sub-surface cavities associated with blisters is the predominant trapping mechanism in tungsten in the case of high fluence exposures. We attribute the lower retention in W-Ta under the investigated conditions to the weaker blistering.
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Surface modification of tungsten and tungsten–Tantalum Alloys exposed to high-flux deuterium plasma and its impact on deuterium retention
Nuclear Fusion, 2013Co-Authors: Y Zayachuk, M H J T Hoen, I Uytdenhouwen, P.a. Zeijlmans Van Emmichoven, D Terentyev, G. Van OostAbstract:Samples of tungsten and tungsten-Tantalum alloy (with 5 mass per cent of Ta) were exposed to high-flux deuterium plasma at different fluences. The surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS). In the high fluence range of similar to 3.5 x 10(26)-10(27)m(-2), multiple large-size blisters are formed on the W surface, while blisters on the W-Ta surface are considerably smaller in size and number. Deuterium retention in this fluence range was found to be systematically higher in W than in W-Ta. Correlation between the evolution of the blistering patterns and the TDS spectra as a function of fluence suggests that trapping in the sub-surface cavities associated with blisters is the predominant trapping mechanism in tungsten in the case of high fluence exposures. We attribute the lower retention in W-Ta under the investigated conditions to the weaker blistering.