Thermal aging effects on surface of 2.5 Me V Fe ion-irradiated Fe–0.6%Cu alloy were investigated using positron annihilation techniques. The samples were irradiated at 573 K to a dose of 0.1 dpa. Their thermal aging ...Thermal aging effects on surface of 2.5 Me V Fe ion-irradiated Fe–0.6%Cu alloy were investigated using positron annihilation techniques. The samples were irradiated at 573 K to a dose of 0.1 dpa. Their thermal aging was performed at 573 K for 5, 50 and 100 h. From the results of Doppler broadening measurement, an obvious trough could be seen in near-surface region from the S parameters and inflection point form at S–W curves. This indicates changes in the annihilation mechanism of positrons in surface region after thermal aging. Coincident Doppler broadening indicates that the density of Cu precipitates in the thermal aged samples decreased, due to recovery of the vacancies.展开更多
A novel Fe-10Cr ferritic/martensitic steel called SIMP was chosen to investigate synergistic effects of H and He on the mechanical properties of structural materials for innovative nuclear energy systems. Sequential a...A novel Fe-10Cr ferritic/martensitic steel called SIMP was chosen to investigate synergistic effects of H and He on the mechanical properties of structural materials for innovative nuclear energy systems. Sequential and separate irradiation experiments on SIMP steel specimens at room temperature using H and He ions with various energy levels were conducted to produce an ion deposition plateau at 300-650 nm. The indentation stress-strain responses were examined using spherical nanoindentation tests after the irradiation experiments. It was found that the sequential irradiation by He and H produced a higher indentation yield stress than separate irradiation, indicating that the hardening was enhanced by the synergy of the H and He irradiation. The micro-mechanism responsible for enhancing the hardening of the SIMP steel through the H and He synergy was investigated using Doppler broadening spectroscopy detection and transmission electron spectroscopy observations.展开更多
Tungsten (W) is a promising candidate for plasma-facing materials (PFMs) in fusion reactors owing to its excellent thermal conductivity, sputtering resistance, and low hydrogen isotope solubility [1]. W PFMs encounter...Tungsten (W) is a promising candidate for plasma-facing materials (PFMs) in fusion reactors owing to its excellent thermal conductivity, sputtering resistance, and low hydrogen isotope solubility [1]. W PFMs encounter the challenges of triple irradiations generated by high-heat loads;high-flux particles, including helium/deuterium (D)/tritium (T);and high-energy neutrons.展开更多
In this study,the influence of hydrogen charging and deformation on the tensile behavior of a 60Fe-12Cr-10Mn-15Cu-3Mo multi-component alloy was investigated using electron microscopy and positron annihilation lifetime...In this study,the influence of hydrogen charging and deformation on the tensile behavior of a 60Fe-12Cr-10Mn-15Cu-3Mo multi-component alloy was investigated using electron microscopy and positron annihilation lifetime spectroscopy.The results show that hydrogen-induced vacancy clusters found in the electrochemically charged hydrogen specimens are responsible for crack initiation.Upon ingress to the microstructure,hydrogen promotes the formation of cell-structured dislocations that are beneficial for the improvement of tensile strength.In addition,hydrogen embrittlement can be mitigated by dislocations that can hinder hydrogen mobility in the deformed specimens.展开更多
基金supported by the National Natural Science Foundation of China(Nos.91026006,91226103,11475193,11475197,11575205and 11505192)Beijing Natural Science Foundation(No.1164017)
文摘Thermal aging effects on surface of 2.5 Me V Fe ion-irradiated Fe–0.6%Cu alloy were investigated using positron annihilation techniques. The samples were irradiated at 573 K to a dose of 0.1 dpa. Their thermal aging was performed at 573 K for 5, 50 and 100 h. From the results of Doppler broadening measurement, an obvious trough could be seen in near-surface region from the S parameters and inflection point form at S–W curves. This indicates changes in the annihilation mechanism of positrons in surface region after thermal aging. Coincident Doppler broadening indicates that the density of Cu precipitates in the thermal aged samples decreased, due to recovery of the vacancies.
基金supported by the National Natural Science Foundation of China under grants(Nos.U1832206,11505246,11605256,91426301,11405231,11575258,11375242,and 11505247)the key projects of the Chinese Academy of Sciences(No.ZDRW-CN-2017-1)。
文摘A novel Fe-10Cr ferritic/martensitic steel called SIMP was chosen to investigate synergistic effects of H and He on the mechanical properties of structural materials for innovative nuclear energy systems. Sequential and separate irradiation experiments on SIMP steel specimens at room temperature using H and He ions with various energy levels were conducted to produce an ion deposition plateau at 300-650 nm. The indentation stress-strain responses were examined using spherical nanoindentation tests after the irradiation experiments. It was found that the sequential irradiation by He and H produced a higher indentation yield stress than separate irradiation, indicating that the hardening was enhanced by the synergy of the H and He irradiation. The micro-mechanism responsible for enhancing the hardening of the SIMP steel through the H and He synergy was investigated using Doppler broadening spectroscopy detection and transmission electron spectroscopy observations.
基金supported by the National Natural Science Foundation of China(Grant No.51720105006)the Science and Technology on Surface Physics and Chemistry Laboratory(Grant No.02020317)
文摘Tungsten (W) is a promising candidate for plasma-facing materials (PFMs) in fusion reactors owing to its excellent thermal conductivity, sputtering resistance, and low hydrogen isotope solubility [1]. W PFMs encounter the challenges of triple irradiations generated by high-heat loads;high-flux particles, including helium/deuterium (D)/tritium (T);and high-energy neutrons.
基金The financial supports from the National Key R&D Project(Grant Nos.2019YFA0210002 and 2019YFA0209904)the National Natural Science Foundation of China(Grant Nos.12005229,12175262,and 11875055)+1 种基金China Post-doctoral Science Foundation(Grant Nos.2019M660795 and 2020T130653)are gratefully acknowledgedThe first author gratefully acknowledges financial support from the Hong Kong Scholars Program of China(XJ2020053).
文摘In this study,the influence of hydrogen charging and deformation on the tensile behavior of a 60Fe-12Cr-10Mn-15Cu-3Mo multi-component alloy was investigated using electron microscopy and positron annihilation lifetime spectroscopy.The results show that hydrogen-induced vacancy clusters found in the electrochemically charged hydrogen specimens are responsible for crack initiation.Upon ingress to the microstructure,hydrogen promotes the formation of cell-structured dislocations that are beneficial for the improvement of tensile strength.In addition,hydrogen embrittlement can be mitigated by dislocations that can hinder hydrogen mobility in the deformed specimens.
