V-4Cr-4Ti is the leading candidate vanadium alloy as structural material of a V-Li blanket. Due to the interaction between Ti and interstitial solutes of C, N, and O, precipitation occurs at 600--700℃, increases the ...V-4Cr-4Ti is the leading candidate vanadium alloy as structural material of a V-Li blanket. Due to the interaction between Ti and interstitial solutes of C, N, and O, precipitation occurs at 600--700℃, increases the alloy strength significantly but reduce its ductility. As the ductility reduction is in an acceptable level, the strengthening might be utilized for the components that are subjected to high stress levels. Although cold work （CW） is known as an effective way to strengthen an alloy, so far few reports were found on strengthening a vanadium alloy by cold rolling.展开更多
A non-destructive and in-situ technique for the measurement of tritium in materials, namely β-ray-induced X-ray spectrometry （BIXS）, has been developed recently. In the present study a V-4Cr-4Ti alloy was pre-heate...A non-destructive and in-situ technique for the measurement of tritium in materials, namely β-ray-induced X-ray spectrometry （BIXS）, has been developed recently. In the present study a V-4Cr-4Ti alloy was pre-heated at 1000℃ for 2 h to form a recrystallization structure before the tritium absorption experiments were conducted. Firstly the hydrogen isotope gas was charazterized by means of a quadrupole mass spectrometer （QMS） and a small-sized ionization chamber. Then hydrogen isotope absorption tests of V-4Cr-4Ti alloy were performed at 400 ℃ and the atomic concentration of hydrogen isotope in V-4Cr-4Ti alloy was estimated as 0.17% with a tritium content of approximately 2.5 ppm. Experimental results indicate that BIXS is a quite useful tool for quantitatively measuring the tritium content and tritium distribution in the surface layers of vanadium alloys and no strong trapping effects of tritium exist in the pre-heated V-4Cr-4Ti alloy.展开更多
Several evaluation techniques of tritium in material have been developed so far, such as imaging plate method or electrochemical etching and thermal desorption analysis, as well as conventional β-ray counting. For th...Several evaluation techniques of tritium in material have been developed so far, such as imaging plate method or electrochemical etching and thermal desorption analysis, as well as conventional β-ray counting. For the latter, its detectable depth is usually limited to a very thin surface region, for example, about 1μm depth for organic and 0.1 μm for metallic materials owing to the shallow escape depth of tritium β-rays.展开更多
The addition of Cr and Ti elements gives V-4Cr-4Ti a ductile-to-brittle transition temperature as low as-140℃,significantly lower than that of pure V.However,the effect of oxygen solute on the deformability of V-4Cr-...The addition of Cr and Ti elements gives V-4Cr-4Ti a ductile-to-brittle transition temperature as low as-140℃,significantly lower than that of pure V.However,the effect of oxygen solute on the deformability of V-4Cr-4Ti remains largely unexplored.Here,it is demonstrated that V-4Cr-4Ti exhibits significantly faster oxygen absorption kinetics compared to pure V.Although alloying with Ti can trap some oxygen solute,the remaining oxygen solute in the matrix severely embrittles the alloy.Profuse dislocation multiplication through kink formation and frequent cross-slips endows V-4Cr-4Ti with excellent low-temperature deformability.In contrast,oxygen-charged V-4Cr-4Ti containing 0.57 wt.%O shows severe embrittlement even at temperatures exceeding 200℃.High concentrations of oxygen solute,combined with Ti and Cr alloying elements,hinder dislocation motion,promote strain localization,and generate numerous super-jogs(sessile structures)and dislocation loops,collectively leading to embrittlement.These findings provide insights into the microscopic oxygen embrittlement mechanisms in V-4Cr-4Ti.展开更多
基金Supported by the Core University Program （CUP） between Japan and China and the National Natural Science Foundation of China （50271025）
文摘V-4Cr-4Ti is the leading candidate vanadium alloy as structural material of a V-Li blanket. Due to the interaction between Ti and interstitial solutes of C, N, and O, precipitation occurs at 600--700℃, increases the alloy strength significantly but reduce its ductility. As the ductility reduction is in an acceptable level, the strengthening might be utilized for the components that are subjected to high stress levels. Although cold work （CW） is known as an effective way to strengthen an alloy, so far few reports were found on strengthening a vanadium alloy by cold rolling.
基金supported by the China-Japan Core University Program(Task1-2A)
文摘A non-destructive and in-situ technique for the measurement of tritium in materials, namely β-ray-induced X-ray spectrometry （BIXS）, has been developed recently. In the present study a V-4Cr-4Ti alloy was pre-heated at 1000℃ for 2 h to form a recrystallization structure before the tritium absorption experiments were conducted. Firstly the hydrogen isotope gas was charazterized by means of a quadrupole mass spectrometer （QMS） and a small-sized ionization chamber. Then hydrogen isotope absorption tests of V-4Cr-4Ti alloy were performed at 400 ℃ and the atomic concentration of hydrogen isotope in V-4Cr-4Ti alloy was estimated as 0.17% with a tritium content of approximately 2.5 ppm. Experimental results indicate that BIXS is a quite useful tool for quantitatively measuring the tritium content and tritium distribution in the surface layers of vanadium alloys and no strong trapping effects of tritium exist in the pre-heated V-4Cr-4Ti alloy.
文摘Several evaluation techniques of tritium in material have been developed so far, such as imaging plate method or electrochemical etching and thermal desorption analysis, as well as conventional β-ray counting. For the latter, its detectable depth is usually limited to a very thin surface region, for example, about 1μm depth for organic and 0.1 μm for metallic materials owing to the shallow escape depth of tritium β-rays.
基金financially supported by the Continuous Basic Scientific Research Project(No.BJ020261223286)。
文摘The addition of Cr and Ti elements gives V-4Cr-4Ti a ductile-to-brittle transition temperature as low as-140℃,significantly lower than that of pure V.However,the effect of oxygen solute on the deformability of V-4Cr-4Ti remains largely unexplored.Here,it is demonstrated that V-4Cr-4Ti exhibits significantly faster oxygen absorption kinetics compared to pure V.Although alloying with Ti can trap some oxygen solute,the remaining oxygen solute in the matrix severely embrittles the alloy.Profuse dislocation multiplication through kink formation and frequent cross-slips endows V-4Cr-4Ti with excellent low-temperature deformability.In contrast,oxygen-charged V-4Cr-4Ti containing 0.57 wt.%O shows severe embrittlement even at temperatures exceeding 200℃.High concentrations of oxygen solute,combined with Ti and Cr alloying elements,hinder dislocation motion,promote strain localization,and generate numerous super-jogs(sessile structures)and dislocation loops,collectively leading to embrittlement.These findings provide insights into the microscopic oxygen embrittlement mechanisms in V-4Cr-4Ti.
