氢气中饱和水份对TiFe0.9Mn0.1合金贮氢性能及其释放氢含水量的影响

用放氢量和露点的方法,研究了在非流动系统中一定温度和放氢压力下,氢气中饱和水份(10~(-6))对TiFe_(0.9)Mn_(0.1)合金贮氢性能及其释放氢含水量的影响。结果表明,氢中饱和水份有降低合金贮氢性能的作用;氢中饱和水份对TiFe_(0.9)Mn_(0.1)合金存在不均匀的和缓慢的毒化反应;合金对原料氢的饱和水份没有浓缩效应,存在有限的稀释作用,其释放氢的含水量与原料氢水份和一定温度、压力下水分压及水份吸附、脱附等因素有关。     

氢气中氧,氮对TiFe0.9Mn0.1合金贮氢性能的影响

采用气相色谱等方法研究了非连续流动氢气中氧、氮对TiFe_(0.9)Mn_(0.1)合金贮氢性能的影响。结果表明,氢中低浓度氧对贮氢合金性能无明显的影响,氢中高浓度氧对贮氢合金有严重的毒化作用和氧毒化的不均匀性及热再生性。贮氢合金对氢气中低浓度氮具有浓缩作用,随放氢量的增加,氢中氮减少。氢气中高浓度氮具有阻止贮氢合金氢化的作用。     

富镧混合稀土贮氢合金分离氢中氪,氙性能的研究

叙述了MINi_(4.5)Al_(0.5)贮氢合金分离氢中氪、氙的基本原理,分析了氢中氪、氙浓度与分离温度的关系,得到了在298K时MINi_(4.5)Al_(0.5)合金与TiFe_(0.86)Mn_(0.1)合金的分离性能基本相似,分离浓度与放氢体积符合N=αe~m方程。     

热处理La-Mg-Ni系贮氢合金微观结构研究进展

热处理对贮氢合金的微观组织结构影响较大。详细综述了La-Mg-Ni系贮氢合金近年来热处理对相结构、相组成、晶胞体积、显微组织影响的研究现状,旨在为改善具有优异电极性能的La-Mg-Ni系贮氢合金微观组织的控制因素提供思路和依据。     

Ti-Mn基Laves相贮氢合金的研究

采用P-C-T曲线测试和XRD分析研究了Ti/Zr比变化对Ti-Mn基Laves相贮氢合金贮氢性能的影响.实验结果表明,随Ti/Zr比降低,合金放氢压力降低,贮氢量略微增加,平台坡度变陡.同时还研究了Mn/Cr比变化对Ti-Mn基Laves相贮氢合金晶体结构、活化性能以及贮氢性能的影响.着重探讨了Mn/Cr比变化时影响合金平衡压力的2个因素.对(Ti0.85Zr0.15)Mn1.4Cr0.2V0.32Fe0.08(x=-0.025,0,0.05,0.1)系列合金,根据其P-C-T测试和XRD分析结果,讨论了x的变化对合金贮氢量、平衡压力、α区宽度的影响.     

Pd含量对Mg-Ni合金相形成及贮氢性能的影响研究

采用机械合金化方法合成了Mg-54.7%Ni-x%Pd(x=0、3、10,质量百分比)贮氢材料.通过X射线衍射分析(XRD)和贮氢性能测试,研究了Pd含量对Mg-Ni合金相形成及贮氢性能的影响.XRD分析表明,在0.30MPa的氩气气氛下球磨30h后,粉末没有形成合金相;但在523K吸氢时,Mg-54.7%Ni-x%Pd(x=0,3)与氢气反应均生成了大量的Mg2NiH4,而Mg-54.7%Ni-10%Pd的氢化物中大部分为MgH2,只形成了少量的Mg2NiH4.贮氢性能测试结果表明,所制备的材料在473K无需活化即可吸氢;同Mg-54.7%Ni-x%Pd(x=0,10)相比,Mg-54.7%Ni-3%Pd吸放氢速度最快,可逆贮氢容量最大(2.82%,质量百分比).     

高性能贮氢电极合金的研究进展

报道了高性能贮氢电极合金的研究进展,主要内容包括AB5型贮氢合金的A侧稀土元素组成、主要杂质元素(Fe,Si,Mg）以及合金制备技术（真空退火处理和快速凝固）对合金的相结构和电化学性能的影响。AB2型Zr基Laves相合金的相结构和相组成与电化学性能的关系,以及若干新型多元Zr基贮氢电极合金的性能。     

熔体快淬对纳米晶和非晶Mg20Ni10-xCox(x≈0～4)合金电化学贮氢性能的影响

为了改善Mg2Ni型合金的电化学贮氢性能,用Co部分替代合金中的Ni.用快淬工艺制备了纳米晶和非晶Mg20Ni10-xCox(x=0、1、2、3、4)贮氢合金,分析了铸态及快淬态合金的微观结构,测试了合金的电化学贮氢性能.研究了Co替代Ni及快淬工艺对合金电化学贮氢性能的影响.结果表明,Co替代Ni不改变合金的Mg2Ni主相,但形成了第二相MgCo2.在快淬(x=0)合金中没有发现非晶相,但快淬(x=4)合金显示了纳米晶、非晶结构,表明Co替代Ni提高了Mg2Ni型舍金的非晶形成能力.熔体快淬显著的改善了合金的电化学贮氢性能,合金放电容量和电化学循环稳定性均随淬速的增加而增加.     

AB2型贮氢合金的表面处理

高容量的贮氢合金电极材料是高比能量ＭＨ－Ｎｉ动力电池的基础。Ｌａｖｅｓ相ＡＢ２型贮氢合金的贮氢量大、无污染、循环寿命长,但锆基Ｌａｖｅｓ相ＡＢ２型贮氢合金存在电极活化困难、电催化性能差、高倍率放电能力低下等缺点,严重影响了Ｌａｖｅｓ相贮氢合金在ＭＨ－Ｎｉ动力电池中的应用,因此贮氢合金的表面处理十分重要。综述了近年来对ＡＢ２型贮氢合金表面处理的研究情况。     

双相MlNi3.7Al0.4Cu0.4微晶贮氢合金的结构及活化性能

测试和分析了新型超声气体雾化双相复合MlNi3.7Al0.4Cu0.4微晶贮氢合金的微观组织结构及电化学活化性能.结果表明,这种贮氢合金的微观结构为双相复合结构,基体为AB5(A≡La,Ce,Nd,Pr,B≡Ni,Al,Cu)相,富稀土的AB相在基体中呈不连续网状分布,在相界面存在淬火裂纹.电化学活化性能优越,活化次数仅为1～3次.     

Application of AFM to study functional nanomaterials prepared by mechanical alloying

Two-phase hard magnetic Nd₂Fe₁₄B/α-Fe nanocomposites and nanocrystalline TiFe electrode materials were prepared by mechanical alloying and heat treatment. The microstructure of both types of functional nanomaterials was investigated by atomic force microscopy. In the case of Nd₂Fe₁₄B magnetic phase, the microstructure refinement was realised by careful heat treatment and Zr addition. AFM investigations showed that Zr reduces a grain size of a parent alloy in the range of 20-40%. More than 90% grains have size below 50 nm, and more than 50% grains have size below 20 nm, which results in enhanced remanence. On the other hand, in TiFe alloy, a fine microstructure is known to improve greatly the properties of hydrogen storage alloys, when compared with their conventional polycrystalline counterparts. Additionally, the substitution of Fe by some amount of nickel improves the activation property of TiFe. Two types of AFM imaging modes, height and deflection, are accurate for agglomerate and grain size presentation, respectively.     

Applicability of life prediction methods to the low cycle fatigue of braze clad AlMn1.0Mg0.5 alloys

The original and modified universal slope methods, the uniform material law, and the modified Diercks equation have been applied to the low cycle fatigue life prediction in the braze clad AlMn1.0Mg0.5 alloys. The experimental data from clad and non-clad, pre-strained and non-pre-strained AlMn1.0Mg0.5 alloys at room temperature and at 75 and 180°C have been used to evaluate the applicability of the life estimation methods. It is likely that there is no universal method to predict the low cycle fatigue lives of all kinds of aluminium alloys. However, the modified universal slope method and the modified Diercks equation provide reasonably good predictions in these braze clad aluminium alloys.     

Ti—Ni形状记忆合金DSC曲线的特征

系统研究了Ｔｉ－Ｎｉ形状记忆合金时效后ＤＳＣ曲线的特征。结果表明，Ｔｉ－Ｎｉ合金的ＤＳＣ曲线分６种类型复杂ＤＳＣ曲线可用不完全循环法分析。根据成分时效工艺不同，Ｔｉ－Ｎｉ合金可发生７种可逆相变。     

TiFe系储氢合金性能改善研究进展

TiFe合金作为一种传统的储氢材料,因其分解压力适中,储氢量较大,原材料储量丰富而引起广泛的研究兴趣。但是该合金存在活化困难、易中毒和滞后大等缺点,严重阻碍了其实际应用。针对TiFe合金的缺点研究者们进行了大量的改性研究。综述了TiFe系储氢合金的研究进展,介绍了改善其储氢性能的方法及其优缺点,并展望了TiFe系合金今后的研究方向和重点。     

高熵合金制备及研究进展

高熵合金目前的研究大多针对块体、粉体、涂层、薄膜等领域,在其他领域的研究较少且缺乏统一分类。本文根据当前高熵合金研究进展,对所有研究的高熵合金种类进行了划分,介绍了元素选取原则,总结了高熵合金制备方法,综述了高熵合金研究机构、研究形式、研究内容等现状,展望了高熵合金应用前景,提出了当前高熵合金机理研究较少、性能研究不全面、热稳定性研究不系统、涂层制备工艺参数有待优化、轻质高熵合金设计、课题研究领域拓展等系列科学问题并给出针对解决方法,对于高熵合金课题未来的应用领域拓展研究方向有一定的指导意义。     

TiFe—LaNi_5复合粉末的活化

TiFe 贮氢合金活化困难。通过在表面上焊接 LaNi_5微粒,TiFe 合金的活化性能得到改善,可以在室温3MPa 氢压下一次完全活化。SEM 和电子探针分析表明,焊有 LaNi_5微粒的 TiFe颗粒具有麻球状结构。焊接于表面的 LaNi_5微粒起着吸氢窗口的作用,促进了 TiFe 的活化。     

Co3Ti基合金在氢气环境中的脆性

Ｃｏ３Ｔｉ和Ｃｏ３Ｔｉ－Ｆｅ合金在氢气环境中存在着严重的脆化现象。Ｃｏ３Ｔｉ合金中的Ｆｅ对合金在氢气中的脆化有延缓作用,但不能完全抑制环境氢脆。Ｃｏ３Ｔｉ合金在氢气中的脆化机理与其在空气中的脆化机理不同。     

Diffusion bonding between Ti -6Al -4V alloy and microduplex stainless steel with copper interlayer

Abstract

In the present study, diffusion bonding was used to join Ti -6Al- 4V alloy to a microduplex stainless steel using a pure copper interlayer. The effects of heating rate and holding time on microstructural developments across the joint region were investigated. After bonding, microstructural analysis including metallographic examination and energy dispersive spectroscopy (EDS), microhardness measurements, and shear strength tests were carried out. From the results, it was seen that heating rate and holding time directly affect microstructural development at the joint, especially with respect to the formation of TiFe intermetallic compounds, and this in turn affects the shear strength of the bonds. A sound bond was obtained with a heating rate of 100 K min ^-1 and holding time of 5 min, and this was related to the small amount of TiFe intermetallics formed close to the duplex stainless steel side at this bonding condition. Although Ti₂Cu and TiFe intermetallics were formed in all specimens, it was seen that the most deleterious intermetallic was TiFe. As the heating rate was decreased and holding time increased the amount of TiFe intermetallics increased, and consequently shear strength decreased. As a result, from the microstructural observations, EDS analysis, microhardness measurements, and shear strength tests, it was concluded that a high heating rate and a short holding time must be used in the diffusion bonding of Ti-6Al- 4V to a microduplex stainless steel when pure copper interlayers are used.     

Recent development of thin film materials for magnetic heads

Recent developments of soft magnetic film materials in the past decade are reviewed. Approximately 20 kinds of alloy systems with high saturation induction of more than 10 kG have been reported in the last decade, although there were only three conventional head materials: Mn-Zn ferrite, Permalloy, and Sendust. A particular focus of the review is nanocrystalline films and multilayer films. Also reviewed are improvements in single-layer homogeneous films of Fe, Fe-Si, Sendust, and Fe/sub 16/N/sub 2/. Almost all the materials reported are Fe-based alloys, and some alloys are nitrogen related: iron-nitride compounds or nitrogen-containing alpha -Fe or Sendust.<>     

Mechanochemical synthesis and hydrogen sorption properties of nanocrystalline TiFe

The equiatomic intermetallic compound TiFe has been prepared by elemental mechanochemical synthesis in a planetary ball mill from Fe and Ti powders. The structural and phase transformations during synthesis were followed using X-ray diffraction. The reaction of the synthesized compound with hydrogen was studied volumetrically. The results demonstrate that the hydrogen capacity of the mechanochemical TiFe is 1.2 wt % at 2.5 MPa. Its absorption isotherm has an extended plateau in the range 1.6–1.7 MPa at room temperature.