Tungsten-potassium(potassium-doped tungsten or WK),initially known from the electric filament industry,is a promising plasma-facing material(PFM)in future fusion facilities like International Thermonuclear Experimenta...Tungsten-potassium(potassium-doped tungsten or WK),initially known from the electric filament industry,is a promising plasma-facing material(PFM)in future fusion facilities like International Thermonuclear Experimental Reactor(ITER).However,the brittle nature of W and irradiation-induced defects of WK materials may result in a risk of deuterium-tritium reaction failure in fusion reactors.Previous studies revealed that advanced W with ultrafine grains and nanostructures might be able to address these problems.However,K-doped W,a rapidly developed material for PFMs,lacks a systematical sum-mary.In this review,we firstly describe the powder metallurgy and plastic deformation for the preparation of WK.Then,the mechanical properties of WK and thermal shock resistance results are reviewed.Important issues such as irradiation damages from neutron,heavy ion,and plasma(H isotope or He)irradiation are also discussed.Hitherto,WK under irradia-tions shows comparable or even better performances compared with other counterparts such as ITER grade pure tungsten.This review could be benefitial to the future efforts of improving the ductility and irradiation tolerance of WK materials.展开更多
Potassium tungsten bronze KxLayWO3 (x>0.5 and y<0.01) was synthesized by rare earth co-permeation method using α-K7[SiMg3(OH2)3W9O37] as the precursor. Binding energies of La, W, O and C were determined by XPS....Potassium tungsten bronze KxLayWO3 (x>0.5 and y<0.01) was synthesized by rare earth co-permeation method using α-K7[SiMg3(OH2)3W9O37] as the precursor. Binding energies of La, W, O and C were determined by XPS. From the XPS data, a peak at 34.21 eV indicates that some W6+ turned into W5+ by rare earth co- permeation. The binding energies La3d were the same in the surface and inner of the composite, showing that rare earth element La could diffuse into the body of the composite and the compound of KxLayWO3 was formed at the same time. The binding energies of O1s in KxLayWO3 surface were 531.4 eV and 532.0 eV, respectively, while peak at 531.4 eV disappeared through etching process. The result implies that the binding energy of 531.4 eV was due to the adsorbent O. In addition, the binding energies of C1s in the surface were 283.5 eV, 285.0 eV and 286.7 eV respectively, while the inner had only one peak at 285.0 eV due to standard C1s. This proves that there was no C in the core.展开更多
Tungsten is one of the most promising plasma-facing materials (PFMs) to be used in the nuclear fusion reactor as divertor material in the future. In this work, W2+-ions bombardment is used to simulate the neutron irra...Tungsten is one of the most promising plasma-facing materials (PFMs) to be used in the nuclear fusion reactor as divertor material in the future. In this work, W2+-ions bombardment is used to simulate the neutron irradiation damage to commercial pure tungsten (W) and rolled tungsten–potassium (W–K). The 7 MeV of 3 × 10^15 W2+-ions/cm2, 3 MeV of 4.5 × 10^14 W2+, and 2 MeV of 3 × 10^14 W2+-ions/cm2 are applied at 923 K in sequence to produce a uniform region of 100 nm–400 nm beneath the sample surface with the maximum damage value of 11.5 dpa. Nanoindentation is used to inspect the changes in hardness and elastic modulus after self-ion irradiation. Irradiation hardening occurred in both materials. The irradiation hardening of rolled W–K is affected by two factors: one is the absorption of vacancies and interstitial atoms by potassium bubbles, and the other is the interaction between potassium bubbles and dislocations. Under the condition of 11.5 dpa, the capability of defect absorption can reach a threshold. As a result, dislocations finally dominate the hardening of rolled W–K. Specific features of dislocation loops in W–K are further observed by transmission electron microscopy (TEM) to explain the hardening effect. This work might provide valuable enlightenment for W–K alloy as a promising plasma facing material candidate.展开更多
基金the National Natural Science Foundation of China(Grant Nos.11775149 and 11475118).
文摘Tungsten-potassium(potassium-doped tungsten or WK),initially known from the electric filament industry,is a promising plasma-facing material(PFM)in future fusion facilities like International Thermonuclear Experimental Reactor(ITER).However,the brittle nature of W and irradiation-induced defects of WK materials may result in a risk of deuterium-tritium reaction failure in fusion reactors.Previous studies revealed that advanced W with ultrafine grains and nanostructures might be able to address these problems.However,K-doped W,a rapidly developed material for PFMs,lacks a systematical sum-mary.In this review,we firstly describe the powder metallurgy and plastic deformation for the preparation of WK.Then,the mechanical properties of WK and thermal shock resistance results are reviewed.Important issues such as irradiation damages from neutron,heavy ion,and plasma(H isotope or He)irradiation are also discussed.Hitherto,WK under irradia-tions shows comparable or even better performances compared with other counterparts such as ITER grade pure tungsten.This review could be benefitial to the future efforts of improving the ductility and irradiation tolerance of WK materials.
文摘Potassium tungsten bronze KxLayWO3 (x>0.5 and y<0.01) was synthesized by rare earth co-permeation method using α-K7[SiMg3(OH2)3W9O37] as the precursor. Binding energies of La, W, O and C were determined by XPS. From the XPS data, a peak at 34.21 eV indicates that some W6+ turned into W5+ by rare earth co- permeation. The binding energies La3d were the same in the surface and inner of the composite, showing that rare earth element La could diffuse into the body of the composite and the compound of KxLayWO3 was formed at the same time. The binding energies of O1s in KxLayWO3 surface were 531.4 eV and 532.0 eV, respectively, while peak at 531.4 eV disappeared through etching process. The result implies that the binding energy of 531.4 eV was due to the adsorbent O. In addition, the binding energies of C1s in the surface were 283.5 eV, 285.0 eV and 286.7 eV respectively, while the inner had only one peak at 285.0 eV due to standard C1s. This proves that there was no C in the core.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11975160 and 11775149)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Tungsten is one of the most promising plasma-facing materials (PFMs) to be used in the nuclear fusion reactor as divertor material in the future. In this work, W2+-ions bombardment is used to simulate the neutron irradiation damage to commercial pure tungsten (W) and rolled tungsten–potassium (W–K). The 7 MeV of 3 × 10^15 W2+-ions/cm2, 3 MeV of 4.5 × 10^14 W2+, and 2 MeV of 3 × 10^14 W2+-ions/cm2 are applied at 923 K in sequence to produce a uniform region of 100 nm–400 nm beneath the sample surface with the maximum damage value of 11.5 dpa. Nanoindentation is used to inspect the changes in hardness and elastic modulus after self-ion irradiation. Irradiation hardening occurred in both materials. The irradiation hardening of rolled W–K is affected by two factors: one is the absorption of vacancies and interstitial atoms by potassium bubbles, and the other is the interaction between potassium bubbles and dislocations. Under the condition of 11.5 dpa, the capability of defect absorption can reach a threshold. As a result, dislocations finally dominate the hardening of rolled W–K. Specific features of dislocation loops in W–K are further observed by transmission electron microscopy (TEM) to explain the hardening effect. This work might provide valuable enlightenment for W–K alloy as a promising plasma facing material candidate.
