The reduced activation ferritic/martenstic steel CLF-1 prepared by the Southwestern Institute of Physics in China was irradiated by helium ions with an energy of 5 keV at room temperature using an electron cyclotron r...The reduced activation ferritic/martenstic steel CLF-1 prepared by the Southwestern Institute of Physics in China was irradiated by helium ions with an energy of 5 keV at room temperature using an electron cyclotron resonance (ECR) ion irradiation apparatus. After the irradiation, the helium retention and desorption were investigated using a technique of thermal desorption spectroscopy (TDS). The experiment was conducted with both the normal and welded samples. Blisters were observed after the helium ion irradiation, and the surface density of blisters in the welded samples was lower than that in the non-welded samples. Three desorption peaks were observed in both the non-welded and welded samples. These desorption peaks corresponded to those of blister ruptures and the helium release from the inner bubbles and the defects. The amount of helium retained in the welded samples was approximately the same as that in the non- welded samples, which was much less than other reduced activation materials, such as vanadium alloy and SiC/SiC composites.展开更多
A cluster dynamics model based on rate theory has been developed to describe the accumulation and diffusion processes of helium in tungsten under helium implantation alone or synergistic irradiationwith neutron,by inv...A cluster dynamics model based on rate theory has been developed to describe the accumulation and diffusion processes of helium in tungsten under helium implantation alone or synergistic irradiationwith neutron,by involving different types of objects,adopting up-to-date parameters and complex reaction processes as well as considering the diffusion process along with depth.The calculated results under different conditions are in good agreement with experiments much well.The model describes the behavior of helium in tungsten within 2D space of defect type/size and depth on different ions incident conditions(energies and fluences)and material conditions(system temperature and existent sinks),by including the synergistic effect of helium-neutron irradiations and the influence of inherent sinks(dislocation lines and grain boundaries).The model,coded as IRadMat,would be universally applicable to the evolution of defects for ions/neutron irradiated on plasma-facing materials.展开更多
This paper studies the helium ions irradiation effects on Nd and Ce co-doped Gd_2 Zr_2 O_7 ceramics. where Nd replaces the Gd site and Ce replaces the Zr site respectively. A series of(Gd_(1-x)Nd_x)_2(Zr_(1-y)C...This paper studies the helium ions irradiation effects on Nd and Ce co-doped Gd_2 Zr_2 O_7 ceramics. where Nd replaces the Gd site and Ce replaces the Zr site respectively. A series of(Gd_(1-x)Nd_x)_2(Zr_(1-y)Ce_y)_2 O_7(0 ≤ x, y ≤ 1) ceramics were irradiated with a 500 keV He ions at room temperature at fluences ranging from 1 × 10^(15) to 1 × 10^(17) ions/cm^2. The irradiated samples were characterized using GIXRD, Raman and SEM measurements. From the GIXRD and Raman observations, the results indicate that all the samples display a deficient fluorite structure after irradiation. The irradiation toleration increases with the irradiation depth increasing under experimental conditions, and Nd_2 Ce_2 O_7 has the best irradiation stability in the(Gd_(1-x)Nd_x)_2(Zr_(1-y)Ce_y)_2 O_7(0≤ x. y≤1). Based on SEM results, the irradiated samples are still relatively dense and uniform, and no second phase exists.展开更多
Through in-situ TEM observation during 30 keV H_(2)^(+)-He^(+) dual-beam irradiation at 723 K,the reaction and transformation of dislocation loops in pure Mo were investigated,especially for<100>loops.Irradiatio...Through in-situ TEM observation during 30 keV H_(2)^(+)-He^(+) dual-beam irradiation at 723 K,the reaction and transformation of dislocation loops in pure Mo were investigated,especially for<100>loops.Irradiation could directly cause the formation of 1/2<111>loops and<100>loops,but 1/2<111>loops were dominant.In-situ observation confirmed the formation mechanism of<100>loops,including direct irradiation induced mechanism,1/2<111>loop direct conversion mechanism,and reaction mechanism of two 1/2<111>loops.Meanwhile,the reaction of two 1/2<111>loops to produce<100>loop should not require the strict size similarity condition.The reaction between 1/2<111>loops could also produce 1/2<111>loop,which was essentially a process in which one loop absorbed another one.The yield strength increment caused by irradiation-induced loops was analyzed,and its saturation value reached0.48 GPa at 0.06 dpa.Compared with single He+irradiation,the number density and average diameter of loops increased significantly and more serious damage was caused under the synergistic effect of hydrogen and helium.The mechanism based on in-situ experimental observation was discussed in depth.展开更多
基金supported by National Natural Science Foundation of China (50701017)Japan-China Core University Program on Plasma and Nuclear Fusion
文摘The reduced activation ferritic/martenstic steel CLF-1 prepared by the Southwestern Institute of Physics in China was irradiated by helium ions with an energy of 5 keV at room temperature using an electron cyclotron resonance (ECR) ion irradiation apparatus. After the irradiation, the helium retention and desorption were investigated using a technique of thermal desorption spectroscopy (TDS). The experiment was conducted with both the normal and welded samples. Blisters were observed after the helium ion irradiation, and the surface density of blisters in the welded samples was lower than that in the non-welded samples. Three desorption peaks were observed in both the non-welded and welded samples. These desorption peaks corresponded to those of blister ruptures and the helium release from the inner bubbles and the defects. The amount of helium retained in the welded samples was approximately the same as that in the non- welded samples, which was much less than other reduced activation materials, such as vanadium alloy and SiC/SiC composites.
基金The authors are very grateful to Dr.Y.Dai of Spallation Materials Technology Spallation Neutron Source Division,Paul Scherrer Institute for his helpful comments and discussions.This work was supported by special Funds for Major State Basic Research Project of China(973)under Grant nos.2007CB925004 and 2008CB717802Knowledge Innovation Program of Chinese Academy of Sciences under Grant no.KJCX2-YW-N35+1 种基金National Science Foundation of China under Grant no.11005124China Postdoctoral Science Foundation funded project under Grant no.20100470863,and Director Grants of CASHIPS.Part of the calculations were performed in Center for Computational Science of CASHIPS.
文摘A cluster dynamics model based on rate theory has been developed to describe the accumulation and diffusion processes of helium in tungsten under helium implantation alone or synergistic irradiationwith neutron,by involving different types of objects,adopting up-to-date parameters and complex reaction processes as well as considering the diffusion process along with depth.The calculated results under different conditions are in good agreement with experiments much well.The model describes the behavior of helium in tungsten within 2D space of defect type/size and depth on different ions incident conditions(energies and fluences)and material conditions(system temperature and existent sinks),by including the synergistic effect of helium-neutron irradiations and the influence of inherent sinks(dislocation lines and grain boundaries).The model,coded as IRadMat,would be universally applicable to the evolution of defects for ions/neutron irradiated on plasma-facing materials.
基金Project supported by the National Natural Science Foundation of China(21507105,51574201)Ministry of Housing and Urban-Rural Development(2014-K3-037)+1 种基金Sichuan Science and Technology Innovation Talent Project(2016119)Scientific and Technical Youth Innovation Group(Southwest Petroleum University)(2015CXTD05)
文摘This paper studies the helium ions irradiation effects on Nd and Ce co-doped Gd_2 Zr_2 O_7 ceramics. where Nd replaces the Gd site and Ce replaces the Zr site respectively. A series of(Gd_(1-x)Nd_x)_2(Zr_(1-y)Ce_y)_2 O_7(0 ≤ x, y ≤ 1) ceramics were irradiated with a 500 keV He ions at room temperature at fluences ranging from 1 × 10^(15) to 1 × 10^(17) ions/cm^2. The irradiated samples were characterized using GIXRD, Raman and SEM measurements. From the GIXRD and Raman observations, the results indicate that all the samples display a deficient fluorite structure after irradiation. The irradiation toleration increases with the irradiation depth increasing under experimental conditions, and Nd_2 Ce_2 O_7 has the best irradiation stability in the(Gd_(1-x)Nd_x)_2(Zr_(1-y)Ce_y)_2 O_7(0≤ x. y≤1). Based on SEM results, the irradiated samples are still relatively dense and uniform, and no second phase exists.
基金supported by the National Natural Science Foundation of China(Grant No.11975191,U1832112 and U1967211)。
文摘Through in-situ TEM observation during 30 keV H_(2)^(+)-He^(+) dual-beam irradiation at 723 K,the reaction and transformation of dislocation loops in pure Mo were investigated,especially for<100>loops.Irradiation could directly cause the formation of 1/2<111>loops and<100>loops,but 1/2<111>loops were dominant.In-situ observation confirmed the formation mechanism of<100>loops,including direct irradiation induced mechanism,1/2<111>loop direct conversion mechanism,and reaction mechanism of two 1/2<111>loops.Meanwhile,the reaction of two 1/2<111>loops to produce<100>loop should not require the strict size similarity condition.The reaction between 1/2<111>loops could also produce 1/2<111>loop,which was essentially a process in which one loop absorbed another one.The yield strength increment caused by irradiation-induced loops was analyzed,and its saturation value reached0.48 GPa at 0.06 dpa.Compared with single He+irradiation,the number density and average diameter of loops increased significantly and more serious damage was caused under the synergistic effect of hydrogen and helium.The mechanism based on in-situ experimental observation was discussed in depth.