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Nb-Ti-Fe双相合金已被证实具有优异的渗氢性能,有望成为替代传统Pd膜的渗氢材料。V和Nb同属于5B族,具有类似的物理化学性质,但是,V-Ti-Fe双相合金组织转变规律和渗氢性能至今无人研究。基于此,本工作对V-Ti-Fe三元合金的显微组织和渗氢行为开展了详细研究,并探索了热处理和电化学腐蚀对改善渗氢性能的可能性。研究结果表明:V-Ti-Fe三元合金体系中存在一个包共晶凝固反应,即L+TiFe2→Bcc-(V,Ti)+TiFe (1 626 K)。液相面投影图中存在三个相区,分别为TiFe相区、TiFe2相区和Bcc-(V,Ti)相区。其中,TiFe相区合金室温组织由初生TiFe相和{Bcc-(V,Ti)+TiFe}共晶结构组成,TiFe2相区合金室温组织由初生TiFe相、TiFe2相和Bcc-(V,Ti)相构成,Bcc-(V,Ti)相区合金室温组织由初生Bcc-(V,Ti)相和TiFe相组成,渗氢性能测试证实了该系合金抗氢脆性能较弱。具体来说,上述三区域内部铸态合金在渗氢实验前均发生了不同程度... 相似文献
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研究了环境气氛、动态渗氢及预渗氢对不同有序度Ni2Cr合金脆化的影响.结果表明,有序度对Ni2Cr合金在室温空气及氢气中的环境氢脆没有明显影响;动态渗氢拉伸时Ni2Cr合金存在严重的氢脆敏感性,无序和高度有序合金比部分有序合金脆化严重;预渗氢时,氢原子通过晶格扩散及晶界扩散进入合金,Ni2Cr合金氢脆敏感性随有序度的增大而减小. 相似文献
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许多重要的金属及其合金在冶炼、服役过程中常由于吸收氢而导致其力学性能和抗腐蚀性能的下降,这些性能下降严重威胁着金属材料在机械制造业、基础设施行业和能源行业中服役的安全。氢对金属材料的影响主要体现为氢脆和氢损伤两个方面,提高材料抗氢性能的关键及前提在于理解氢与常见材料微观缺陷的交互作用。近些年来原位透射电镜技术、定量纳米力学测试技术、原子探针技术等实验手段的快速发展极大地促进了氢脆/氢损伤微观机理的研究。简要综述了氢脆/氢损伤微观机理研究领域的研究进展,重点关注了氢对空位、位错、界面等材料微观缺陷行为的影响。 相似文献
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一、前言 美国宇航局(NASA)的新一代航天飞机(X-30)上,准备取消机身的防热瓦片来减轻自身重量,采用液态氢强制冷却机架和蒙皮,钛铝金属间化合物(α_2-Ti_3Al和γ-TiAl)是最有希望的候选材料。然而,许多学者研究指出,氢对Ti_3Al基金属间化合物的力学性能有较大的影响,且能形成氢化物。单相TiAl合金室温延性很差,通过添加合金元素(V、Cr、Mn)得到的双相(γ α_2)TiAl合金,其延性有较好的改进,但是,新近研究表明,这种合金亦能形成氢化物,确实具有氢脆敏感性。尽管如此,人们依然努力寻找抗氢脆性能好的钛铝金属间化合物,最近K.S.Chan研究三种显微组织的Ti_3Al基合金后,认为精细网篮(fine basketweave)组织具有抗氢脆能力,且是很有发展的容忍氢材料。本文的目的是采用多种手段较深入研究网篮组织Ti_3Al基合金的氢脆敏感性及其氢致断裂行为。 二、材料和实验方法 本实验用料是真空非自耗电弧炉熔炼制成的铸锭,在β相区锻造加工至厚度16mm的板材,室温冷却。合金成分为Ti-24Al-11Nb(at%)。将锻造合金板材经线切割 相似文献
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为了研究氢对Ti-6Al-4V合金室温压缩性能的影响,采用Zwick/Z100型材料试验机对置氢Ti-6Al-4V合金进行了压缩试验,并利用OM、XRD和TEM等材料分析方法对合金的微观组织进行了观察.研究表明:置氢前,Ti-6Al-4V合金由等轴的α相和β相组成,置氢后,出现马氏体组织和氢化物;随氢含量增加,马氏体和剩余β相数量增多;氢提高了Ti-6Al-4V合金的抗压强度和塑性等室温压缩性能,最大增幅分别为33.9%和56.3%;置氢Ti-6Al-4V合金抗压强度的提高主要归因于氢的固溶强化、马氏体相变强化和氢化物强化;塑性指标的提高主要是置氢合金中塑性β相数量的增多所致. 相似文献
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Studying hydrogen behavior in alloys and the mechanical properties of alloys are essential to various practical uses,such as separation membranes,as well as hydrogen embrittlement protection.In order to further develop the non-Pd-alloy membranes used in hydrogen separation,the mechanical,thermal properties of V14NiM(M= Al,Fe,Si,Ti,Zn)and hydrogen solubility and diffusion behaviors of V-based ternary alloys were studied by first principles calculation.The results indicated that the hydrogen solution energies of V-Ni-M are greater than pure vanadium.And the mono-vacancy in pure vanadium can capture 6 H atoms while the V-Ni-M alloys can only capture 5 H atoms.Therefore,the V-Ni-M alloys exhibit lower solubility of hydrogen and higher brittleness resistance to embrittlement compared with pure vanadium.And the diffusion coefficients of V-Ni-M alloys are smaller than that of pure vanadium thanks to smaller hydrogen solubility.The hydrogen solubility and hydrogen permeability can maintain relatively balanced.The study of mechanical properties suggests that the V-Ni-Ti has the best resistance to deformation and pure vanadium has the best ductility.Moreover,V-Ni-Si alloy has the smallest thermal expansion coefficient in the temperature range of 473-723 K,which is the temperature of hydrogen separation,indicating that V-Ni-Si is the best for hydrogen separation according to thermal properties. 相似文献
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A new methodology for interpreting hydrogen permeation test data has been proposed with the objective of determining hydrogen permeability, solubility and diffusivity in materials containing surface-coating layers. The mathematical development of equations has been undertaken for steady-state hydrogen permeation conditions allowing the determination of all parameters of interest for the composite material and the coating layer itself. For a single-layered material, a set of three statistically significant permeation tests is enough to determine all variables for the substrate, the composite material and the coating layer. This methodology has been applied to published results on the hydrogen permeation in nitrogen ion-implanted extra-low carbon steel, showing that the hydrogen diffusion coefficient in such a coating layer is several orders of magnitude lower than that in the substrate. The hydrogen solubility in the layer is, by contrast, increased. The magnitudes of these effects depend on the nitrogen concentration in the surface layer. 相似文献
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Study of hydrogen-assisted cracking and measurement of diffusible hydrogen content in different Cr-Mo steel welds shows that
under identical conditions, susceptibility to cracking increased and diffusible hydrogen content decrease with increase in
alloy content. Hydrogen permeation studies show that hydrogen diffusivity decreases and solubility increases with increase
in alloy content. Thus decrease in diffusible hydrogen content with increase in alloying is attributed to increase in apparent
solubility and decrease in apparent diffusivity of hydrogen. Analysis of the results indicates that variation of diffusible
hydrogen content and apparent diffusivity of hydrogen with alloy content can be represented as a function of carbon equivalent
CE1 originally proposed to predict the hardness in the heat-affected zone of alloy steel welds. 相似文献
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《Materials Science & Technology》2013,29(10):1179-1187
AbstractThe influence of hydrogen on the mechanical properties of four austenitic CrNiMo and CrMn alloys with nitrogen contents up to 0.57 wt-% were investigated concerning their resistance against hydrogen embrittlement in correlation to nitrogen content, chemical composition, and hydrogen diffusivity and solubility. Tensile tests were carried out at room temperature and at strain rates between 10-4 and 10-6 s-1 with simultaneous hydrogen charging and after precharging to different hydrogen contents. The mechanical properties have been found to be dependent on both strain rate and hydrogen content in the material. Simultaneous hydrogen charging and mechanical testing have accelerated the failure process owing to a faster hydrogen uptake especially at low strain rates. Hydrogen has shown a softening effect in the elastic range of the stress strain curve, which becomes more pronounced with decreasing strain rate. The favoured mechanism of hydrogen damage of alloys with high nitrogen contents seems to be the hydrogen enhanced localised plasticity mechanism. A correlation between hydrogen embrittlement and stress corrosion cracking has been discussed. It has been established that both the damaging processes in nitrogen containing steels are influenced by the same mechanism. 相似文献
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An Overview of Hydrogen Interaction with Amorphous Alloys 总被引:2,自引:0,他引:2
Theories, experimental results and applications associated with hydrogen behavior in amorphous metals and alloys are reviewed. An emphasis is made on the potential use of these advanced materials for hydrogen storage technology. Therefore, several properties that are especially relevant for such applications are assessed. These include structural models for hydrogen occupancy, sorption characteristics, solubility, diffusion behavior and thermal stabilities. Hydrogen effects on the mechanical properties and fracture modes of glassy metals are also presented, and possible mechanisms of hydrogen embrittlement are discussed. Similarities and differences between hydrogen behavior in amorphous and crystalline metals and alloys are discussed in detail. 相似文献
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使用^1H核磁共报分析方法,证明聚丙烯酸酯的三氯甲烷溶液中氢键的存在,并研究了三氯甲烷在聚丙烯酸酯中的溶解扩散行为.由于氢键存在加强分子间相互作用,使得溶解性增强,扩散性减小.使用LFHB-EOS模型计算溶解性,自由体积理论推算扩散系数,同时考虑耐溶剂基膜的抑制溶胀效果,建立数学模型计算渗透通量.对高分子溶液相平衡计算而言,当高分子的分子量大于一定值以后,溶剂的溶解性与分子量无关.三氯甲烷在充填型复合膜中的渗透通量计算结果和蒸汽渗透实验测定基本一致,表明以化工热力学的物性推算为基础进行有机溶剂分离膜设计研究在合有氢键作用的极性溶剂体系取得成功。 相似文献
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The hydrogen permeation behaviour of iron- and nickel-based amorphous alloys was characterized using electrochemical methodology
and compared with the properties of crystalline metals and alloys. The materials studied were amorphous Fe40Ni38Mo4B18, Fe74Ni4Mo3B17,
Fe78B13Si9 and Ni81P19, as well as a crystalline low-carbon steel, pure nickel and pure palladium. The double potentiostatic
electrochemical hydrogen permeation tests were performed at 40°C using a 0.1 N NaOH solution as electrolyte. It was found
that the hydrogen diffusivity in the iron-based amorphous alloys is a few orders of magnitude lower than in carbon steel and
iron, while a much smaller difference exists between Ni81P19 and pure nickel. Furthermore, the amorphous alloys showed a strikingly
greater capacity to dissolve hydrogen in solid solution compared with their crystalline counterparts. In some cases, their
apparent hydrogen solubility was even greater than that for the liquid metal of the main element present in their chemical
composition.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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为改善Ti(Cr-Mn)2 AB2型合金的储氢性能,采用A侧过化学计量和过渡金属部分替代Mn进行多元合金化,系统研究了Tix(Cr-Mn-M)2(x=1.0,1.1;M=V、Fe、Ni、Cu)合金的储氢性能.研究结果表明,V、Fe、Ni、Cu部分替代Mn进行多元合金化后,合金主相仍保持C14(MgZn2)型Laves相,合金晶胞体积增大.合金化元素部分替代Mn后合金的活化性能得到明显改善,合金吸放氢量增大,吸放氢压力滞后减小.除Fe使合金放氢平台压力有所升高外,其余合金化元素均使合金的吸放氢平衡压力有不同程度的降低,这是由于合金的晶胞体积增大所致.在所形成的合金中,以Ti1.1Cr1.2Mn0.5CuO0.3的综合性能最好,其室温下吸放氢量分别达到1.95%和1.72 9,6(质量分数).采用该合金与自制的轻质高压储氢容器(工作压力为40MPa)复合组成金属氢化物复合式高压储氢器,对其储氢密度的计算结果表明,当储氢合金的填充量(体积分数)达到0.20时,该复合式储氢器总的体积储氢密度将提高57%. 相似文献
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It is shown that aluminum, Al-Mg-Mn-Fe (Alustar), Al-Mg-Mn-Fe-Si-Cr (PA13), and Al-Zn-Mg-Mn-Fe-Si-Cr (Pa47) alloys are sensitive to hydrogen embrittlement in the course of the tests carried out at low strain rates in a 0.01 N NaOH solution. The stress-strain curves, time to failure, and the character of fracture surfaces of specimens tested in air and under the conditions of cathodic polarization are compared. The parameters of hydrogen transport and its entrapping by hydrogen traps are studied on the basis of the data of electrochemical measurements of hydrogen permeation and vacuum extraction. The morphology of inclusions is estimated by the method of numerical metallography and their chemical composition by the method of EDS analysis. Despite distinctions in the chemical and phase compositions of alloys, we observe the dependence of the sensitivity to hydrogen embrittlement on the parameters of hydrogen transport and its entrapping by irreversible traps and some other microstructural characteristics. Under the conditions of electrolytic hydrogenation, the PA13 alloy reveals hydrogen-enhanced plasticity.Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 40, No. 3, pp. 88–94, May–June, 2004. 相似文献
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《Materials Science & Technology》2013,29(12):1236-1239
AbstractHydrogen permeation and diffusivity were studied electrochemically at temperatures between 283 and 343 K at constant current for annealed and hardened AISI 420 and annealed AISI 430 stainless steel. Permeation rate, effective diffusivity, and solubility were calculated from these data. Annealed AISI 420 shows higher permeation rate and lower diffusivity than annealed AISI 430 stainless steel. Hardened AISI 420 has the highest permeation rate and lowest effective diffusivity. The calculation of solubility values from permeation data is in good agreement with the values obtained using a newly developed electrochemical hydrogen solubility measurement technique.MST/1026 相似文献