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1.
Ultra-high vacuum gaseous hydrogen permeation experiments on Fe3Al-based alloy were performed in the temperature range of 330∼450°C with an upstream hydrogen pressure between 3. 38×104 Pa and 7.28×104 Pa. The results show that the hydrogen diffusivity and permeability in Fe3Al-based alloy obey Arrhenius relationship in the experimental temperature range and the hydrogen permeation process is controlled
by the lattice diffusion of hydrogen at relative high temperature. The activation energy of hydrogen diffusion in the Fe3Al-based alloy was found to be 75 kJ/mol.
Supported by the National Natural Science Foundation of China (59895157) 相似文献
2.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ ＩｒｏｎａｌｕｍｉｎｉｄｅｓｂａｓｅｄｏｎＦｅ3 Ａｌｈａｖｅｍａｎｙａｄｖａｎｔａｇｅｓｆｏｒｓｔｒｕｃｔｕｒａｌｕｓｅｓａｔｅｌｅｖａｔｅｄｔｅｍｐｅｒａｔｕｒｅｂｅｃａｕｓｅｏｆｔｈｅｉｒｅｘｃｅｌｌｅｎｔｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅａｎｄｒｅｌａｔｉｖｅｌｙｌｏｗｍａｔｅｒｉａｌｃｏｓｔ.Ｈｏｗｅｖｅｒ,ｔｈｅｓｅａｌｌｏｙｓｈａｖｅｎｏｔｙｅｔｆｏｕｎｄｗｉｄｅｓｐｒｅａｄｕｓｅｂｅｃａｕｓｅｔｈｅｙｅｘｈｉｂｉｔｐｏｏｒｄｕｃｔｉｌｉｔｙａｎｄｂｒ… 相似文献
3.
The mechanism involving the effect of disorder/order transformation on the environmental embrittlement in gaseous H2 is summarized. It is shown that there is no hydrogen embrittlement in disordered state of Kurnakov type intermetallics in gaseous H2. However, the H2-induced environmental embrittlement for the ordered alloy having identical chemical composition becomes severer as the degree of the order increases. The results of testing on the ion gage turned on and off during tensile testing show that the more sensitive to H2-induced hydrogen embrittlement for ordered alloy than disordered one is attributed to the fact that atomic ordering may accelerate the kinetics of the catalytic reaction to produce more atomic hydrogen. The results on simultaneous hydrogen charging show that disordered alloys embrittled as hydrogen atoms are forced into the material implying that the embrittlement of ordered alloy in gaseous H2 is also due to the acceleration of the kinetics of catalytic reaction. The above suggestion was further verified by the adsorption tests of Ni3Fe intermetallics powder. It is shown that the amount of chemically adsorbed hydrogen in ordered state is significantly larger than that adsorbed by the disordered alloy, indicating that the more sensitive to H2-induced embrittlement in the ordered state of alloy is essentially due to the accelerated catalytic reaction. 相似文献
4.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｏｗｉｎｇｔｏｉｔｓｈｉｇｈｈｙｄｒｏｇｅｎ ｓｔｏｒａｇｅａｂｉｌｉｔｙ ,ｌｏｗｃｏｓｔａｎｄａｂｏｕｎｄｉｎｎａｔｕｒａｌｒｅｓｏｕｒｃｅｓ ,Ｍｇ ｂａｓｅｄａｌｌｏｙｂｅ ｃｏｍｅｓａｃｏｍｐｅｔｉｔｉｖｅｈｙｄｒｏｇｅｎ ｓｔｏｒａｇｅｍｅｄｉｕｍｗｈｉｃｈｃａｎｂｅｕｓｅｄｉｎＮｉ ＭＨｂａｔｔｅｒｙａｎｄｆｕｅｌｃｅｌｌ.Ｔｈｅｅｌｅｃ ｔｒｏｃｈｅｍｉｃａｌｍｅｔｈｏｄｈａｓｂｅｅｎｕｓｅｄｉｎｔｈｅｓｔｕｄｙｏｆｈｙ ｄｒｏｇｅｎａｔｉｏｎ/ｄｅｈｙｄｒｏｇｅ… 相似文献
5.
1IntroductionNickel-based alloys containing 20 -30 wt % Mo isknown to be essential for corrosion resistance in re-ducing media[1],especially for resistance to HCl at alltemperatures and concentrations[2]. However , uponexposure to elevated temperatures in the range of600 -800 ℃,these alloys suffer an al most completeloss of roomtemperature ductility as a result of long-range ordering (LRO) to Ni4Mo .It is considered thatthe loss of ductility mainly results from the environ-mental embrittle… 相似文献
6.
The fracture behavior of disordered and ordered Ni4Mo alloy was investigated by tensile tests in hydrogen gas or during hydrogen charging. The results show that the ductility of the disordered alloy decreased slightly with the hydrogen pressure increasing, while that of the ordered alloy decreased rapidly with the hydrogen pressure increasing. However, the ductility of both disordered and ordered alloys reduced similarly seriously with the charging current density increasing. Therefore, the mechanism of order-induced embrittlement of Ni4 Mo alloy in hydrogen gas is supposed to be that atomic order accelerates the kinetics of the catalytic reaction for the dissociation of molecular H2 into atomic H. 相似文献
7.
The room temperature tensile properties of cold-rolled and annealed Fe3(Al,Cr,Zr) alloy are similar to those of warm-rolled Fe3Al alloys. The cold-rolled Fe3(Al,Cr,Zr) alloy is also susceptible to test environments. It has been shown that the ductility in various environments decreases
in sequence of oxygen-oil-air-distilled water. The results of X-ray diffraction analysis show that (211) preferred orientation
of B2 phase appears in cold-rolled Fe3(Al,Cr,Zr) alloy after recrystallization annealing.
Supported by the National Natural Science Foundation of China (59895157) and the Natural Science Foundation of Shanghai Municipal
Commission of Science and Technology (98ZE14020) 相似文献
8.
T. P. Radhakrishnan 《Resonance》2006,11(11):88-93
Carbon dioxide is a fascinating molecule; its gaseous, liquid, solid and even supercritical fluid states have unique properties
and applications. The linear triatomic structure of carbon dioxide molecule with two carbon-oxygen double bonds is all too
familiar. However a whole new world has been opened up by high pressure-high temperature experiments that effected the polymerization
of this small molecule into a covalent network structure with carbon-oxygen single bonds. The crystalline and amorphous forms
of carbonia are built up of linked tetrahedral CO4 units. 相似文献
9.
In this paper the tensile properties of both ordered and disordered Ni-24Fe and Ni-24Fe-0.03%B （wt%） alloys in gaseous hydrogen was investigated. The result shows that the ductility of the disordered Ni3Fe is significantly larger than that of ordered material in gaseous hydrogen. However, the ductility of ordered Ni3Fe doped with 0.03%B is nearly the same as that of disordered one indicating the obvious suppressing effect of boron on the H2-induced embrittlement. Based on the segregation behavior of boron in Ni3A1, it is proposed that the suppressing effect of boron in Ni3Fe on the H2-induced embrittlement is attributed to the segregation of boron on grain boundaries, thereby reducing the hydrogen diffusivity along the grain boundaries. 相似文献
10.
The extractive reaction process of oxygen-working solution-water three-phase system for the production of hydrogen peroxide by the anthraquinone method was investigated in a sieve plate column of 50 mm in internal diameter. The oxidation reaction of anthrahydroquinone in the working solution with oxygen and the extraction of hydrogen peroxide from the working solution into aqueous phase occurred simultaneously in the countercurrent mode. The agitating effect caused by gaseous phase made the droplets of the dispersed phase become smaller, thus, increasing the liquid-liquid interfacial contact areas and resulting in the improvement of the mass transfer velocity. Results showed that the gas-agitation had a beneficial effect on the extraction of hydrogen peroxide from the working solution into the aqueous phase： the concentration of hydrogen peroxide in the raffinate decreased with the increase of the gaseous superficial velocities： and the concentration of H2O2 in the raffinate increased with the increase of the dispersed phase superficial velocity at the same superficial velocity of the gaseous phase. In the G-L-L extractive reaction process, with the increase of the gaseous superficial velocities, both the conversion of the anthrahydroquinone oxidation and the extraction efficiency of hydrogen peroxide first increased significantly, then increased gradually. 相似文献
11.
A significant temperature raise within hydrogen vehicle cylinder during the fast filling process will be observed, while the strength and fatigue life of the cylinder will dramatically decrease at high temperature. In order to evaluate the strength and fatigue of composite hydrogen storage vessel, a 70-MPa fatigue test system using hydrogen medium was set up. Experimental study on the fatigue of composite hydrogen storage vessels under real hydrogen environment was performed. The experimental results show that the ultimate strength and fatigue life both decreased obviously compared with the values under hydraulic fatigue test. Furthermore, fatigue property, failure behavior, and safe hydrogen charging/discharging working mode of onboard hydrogen storage vessels were obtained through the fatigue tests. 相似文献
12.
The hydrogen diffusion behavior of single crystal stoichiometric NiAl was investigated.The results show that the dydrogendiffusivity and permeabilty of single crystal stoichiometric NiAl obey Arrhenius relationship in the experimental temperature range.The activation energy of hydrogen diffusion in single crystal stoichiometric NiAl is about 45 kJ/mol. 相似文献
13.
Wang Xingqing 《上海大学学报(英文版)》1998,2(4):305-310
Ａｌｕｍｉｎｕｍ ＡｌｌｏｙｓTX１ＩｎｔｒｏｄｕｃｔｉｏｎＦｅ－Ａｌｉｎｔｅｒｍｅｔａｌｉｃｓｈａｖｅｇｒｅａｔｐｏｔｅｎｔｉａｌｉｔｉｅｓｆｏｒｓｔｒｕｃｔｕｒａｌａｐｐｌｉｃａｔｉｏｎｓｏｗｉｎｇｔｏｔｈｅｉｒｇｏｏｄｍｅｃｈａｎｉｃａｌｐｒｏｐ... 相似文献
14.
Hui Xu Ph. D. Kai-yuan He Shu-li He Li-zhi Cheng Yuan-da Dong Xue-shan Xiao 《上海大学学报(英文版)》1999,3(4):318-320
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ ＦｅｒｉｃｈｎａｎｏｃｒｙｓｔａｌｌｉｎｅＦｅＺｒＢａｌｌｏｙｓｓｉｍｕｌｔａｎｅｏｕｓｌｙｓｈｏｗｇｏｏｄｓｏｆｔｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓａｎｄｌａｒｇｅｓａｔｕｒａｔｉｏｎｍａｇｎｅｔｉｚａｔｉｏｎ［１,２］．Ｔｈｅｒｅａｒｅｍａｉｎｌｙｔｗｏｐｈａｓｅｓｉｎｔｈｅａｌｌｏｙｓｗｉｔｈｏｐｔｉｍｕｍｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓ：ａｎａｎｏｃｒｙｓｔａｌｌｉｎｅαＦｅｐｈａｓｅａｎｄａｎｉｎｔｅｒｇｒａｎｕｌａｒａｍｏｒｐｈｏｕｓｐｈａｓ… 相似文献
15.
马梦兰 《天津大学学报(英文版)》2000,6(2):162-165
开发了一种用于钢铁的化学热处理工艺——周期氮碳共渗 .该工艺是靠在封闭体积中由三嗪聚合物试剂所升华和分解的气相产物在工件表面形成涂层而处理工件的 .针对不同应用 ,对 F e-N-C系合金该工艺适用的温度范围很宽 ,既可低温氮碳共渗 ,也可超越低温做高温氮碳共渗 .该工艺还十分简便、经济易于控制 ,而且是无污染工艺 ,不像传统化学热处理工艺那样向大气排放有害气体 . 相似文献
16.
Structure and Magnetic Propoerty of Amorphous Fe—Ni Particles prepared by Mechanical Alloying 总被引：1，自引：0，他引：1
The amorphous Fe67.5 alloy particles have been prepared by mechanical alloying(MA) process of elemental powders.The crystallization is observed at temperature around 405℃ by means of differential thermal analyzer,It is found that the coercivity Hc and the effective magnetic anisotropy value of amorphous phase are not far from that of crystal phase.The magnetization behavior of amorphous and nanocrystalline samples prepared by mechanical alloying and milling process are quite similar,they obey 1/H law at middle-high field and 1/H^2 at higher field.The 1/H field dependence is attributed to a large number of dislocations created during MA process.The studies on the 1/H^2 field dependence reveals that magnetization of Fe-Ni ultrafine particles are governed predominantly by internal stress fields induced by MA process. 相似文献
17.
TiAl金属间化舍物热加工窗口非常狭窄,同时对应变速率非常敏感,通常轧制工艺很难同时满足各参数要求．本文采用刚塑性有限元法,通过改变被加工工件的包套厚度、转移时间等工艺参数,对TiAl合金板材包套轧制的转运过程进行了三维有限元模拟,重点分析了温度的变化规律,优化了包套设计方案．结果表明：通过增加包套明显可以提高保温效果和坯料的均温性;隔热层对提高包套和合金板坯的温差效果明显,有利于调整包套和合金板坯材料的力学性能使之相互匹配;包套厚度、转移时间对合金温降影响较大,通过改变包套厚度可以控制温降过程并达到调整包套和合金板坯材料的力学性能使之相互匹配的目的．本文模拟结果可以为TiAl合金板材轧制工艺设计提供参考． 相似文献
18.
Evolution of Surface Oxide Film of Typical Aluminum Alloy During Medium-Temperature Brazing Process简 总被引：1，自引：0，他引：1
The evolution of the surface oxide film along the depth direction of typical aluminum alloy under medium-temperature brazing was investigated by means of X-ray photoelectron spectroscopy （XPS）. For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the en-richment of Mg element on the surface was not detected and the oxide film was pure Al2O3. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al2O3. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl2O4 was formed with a thickness of about 130 nm. The alloy-ing elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during medium-temperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al2O3. 相似文献
19.
高温质子导体在气体传感器,燃料电池,氢泵等方面有着十分广阔的应用前景,因此,作为一类新型材料,日益引起世界各国科学家的浓厚兴趣。介绍了高温质子导体的研究现状、应用前景,组成结构、传导机制、存在的问题及发展方向。 相似文献
20.
The photocatalytic activity of the mixtures of TiO2 with the rare earth oxide La was investigated. The study on the effect of the rare earth oxide content, calcinating temperature
and calcinating time on the performance of the mixture revealed that sample treated under higher temperature and longer time
had higher photoactivity than pure TiO2. The experimental results of polycrystalline X-ray diffraction showed that the extent of the lattice expansion varied with
the variation of calcinating temperature of time. It is suggested that this might be due to the variation of La content diffused
into the TiO2 lattice. The La in the lattice may inhibit the recombination of photogenerated electron-hole pairs and thus enhance the photoactivity. 相似文献