铝锂合金中铈与杂质含量对延伸率及再结晶的作用

研究了铈及有害杂质含量对２０９０及８０９０铝锂合金薄板延伸率和再结晶状态的影响，得出了再结晶组织参数与板材横向延伸率之间的关系。Ｃｅ的微合金化作用在含一定量Ｆｅ、Ｓｉ杂质的２０９０合金和含一定量Ｎａ、Ｋ杂质的８０９０合金中表现得比较明显，当各种杂质共存且含量较高时，Ｃｅ对８０９０合金的延伸率仍有一定的有利作用。随Ｃｅ及杂质含量变化，若两类合金的再结晶体积、粗晶体积及晶粒平均宽度增加，则其延伸率下降，随晶粒长宽比增加，２０９０合金的延伸率增加而８０９０合金的延伸率下降。     

稀土元素对2090铝锂合金疲劳短裂纹门槛值的影响

测出２０９０铝锂合金的ΔＫｔｈ～Δａｔｈ，ΔＫｃｌ．ｔｈ～Δａｔｈ等曲线，并选用７０７５铝合金作对比试验，定量地评定了该合金疲劳短裂纹扩展抗力，探明了基短裂纹效应强的本质原因。同时，研究了稀土元素铈的影响。结果表明，在２０９０铝锂合金中添加微量铈，可较大提出其Δｋｉ，也有益于其ΔＫＣｌ．ｔｈ，因此，不仅消除了该合金疲劳短裂纹扩展抗力低的本质因素，还使其疲劳长裂纹扩展抗力进一步提高。     

铈对锂在铝电极上电极过程的影响

利用循环钛安法和计时电流法研究了在铈在铝电极上的电极过程和铈对锂在铝电极上电有过程的影响。铈不仅改善了锂铝合金的电化学性能，而且改进了铝基体材料的物理性能。为制备锂铝合金阳极提供了依据。     

磁场对含稀土铝锂合金断裂特征的影响

以含铈铝锂合金为研究对象，研究了磁场对含稀土铝锂合金时效过程的影响，从断裂特征及微观组织两方面分析了磁场作用规律。实验结果表明：未加磁场时，合金的断裂特征以理断裂为主；扁平晶粒厚度不匀，在磁场作用下，此合金的断裂特征与微观组织发生明显改观，随磁感应强度增强，合金主断裂面上准解理断裂特征减弱，同时二次裂纹增多，分层比较升高；扁平晶粒厚度变薄，尺寸趋于均匀。用少体物理理论，探讨了磁场对含稀土合金原子扩散过程的影响，为进一步研究稀土元素在磁场中的行为及其局域效应提供了一定的实验依据。     

铈、锂盐对铝阳极氧化膜的协同封闭作用

研究了铈、锂盐在铝阳极氧化膜封闭处理中的协同作用.场发射扫描电镜和X射线衍射谱对铈、锂盐协同封闭前后铝阳极氧化膜形貌和结构的研究结果表明，封闭后膜表面的孔洞消失，封闭产物分布均匀，封闭后膜仍然以非晶态形式存在.根据X射线光电子能谱的结果，封闭后的膜主要由含结晶水的Al2O3及铈、锂的混合氢氧化物组成，同时膜中还含有及封闭溶液组分中的一些阴离子.电化学阻抗谱的研究结果表明铈、锂盐协同封闭能够显著提高膜的耐蚀性能.在实验结果基础上，初步认为铈、锂盐封闭是通过生成结构紧密的封闭产物填充、覆盖膜孔，从而显著提高铝阳极氧化膜的耐蚀性能.     

铈对锂铝合金阳极充放电性能的影响

研究了铈对锂铝合金阳极充放电性能的影响。在锂铝合金阳极中添加 0 5%～ 1 5% (质量分数 )铈 ,可增大电池的放电容量和电压 ,改善锂铝合金阳极的表面形貌。添加铈的多孔锂铝合金阳极具有理想的充放电性能。     

锂在铝合金电极上的析出电位和扩散系数

铝锂合金是一种新型的航空材料,近十年来获得了迅速的发展。1985年发展了熔盐电解法制备铝锂合金新工艺。该法与其他物理冶金法相比,具有节省能源,设备简单,合金产品纯度高等优点。本文测得的析出电位及扩散系数为熔盐电解法制备铝锂合金提供了重要的参考数据。     

稀土元素对二次锂电池中Li—Al负极材料电化学行为的影响

用纯锂作二次锂电池的负板材料有形成锂枝晶和钝化膜的缺点,采用在铝或其他金属如钙、镁、锡上欠电位沉积锂形成锂合金代替纯锂,对克服上述缺点有一定效果.本文报导了以稀土铝合金代替纯铝作基底欠电位沉积锂,在LiClO_4/碳酸丙烯酯电解液中稀土对改进电极性能有有益的影响.     

铈在共晶铝硅合金中分布不均匀性的研究

应用放射性强度计数法和自射线照相法,测定了铝硅共晶合金熔体中不同部位的铈含量及其在微观组织中的分布。结果表明,铈的分布存在着宏观及微观偏析,并随铈含量增加而加剧。     

铈对多孔锂铝合金阳极的影响

研究了含多孔锂铝合金阳极的制备方法,讨论了对多孔锂铝合金阳极物理机械性能的影响,测试了含铈多孔锂铝合金阳极的充放电性能。实验结果显示,,采用ＮａＣｌ为成孔物质以１００－１５０ＭＰａ压力成型和５５０－５７０℃温度烧结,可以获得性能理想的多孔孔铝;以多孔铝为基体,用电化学方法合成的含０．５％－１．５％铈多孔β－锂铝合金阳极具有理想的充放电性能。     

铈在Fe-28Al合金中的作用

以稀土元素Ｃｅ为微合金化元素，研究了Ｃｅ对Ｆｅ３Ａｌ二元合金（Ｆｅ２８Ａｌ）室温力学性能的影响，采用光学显微镜、扫描电镜、透射电镜、Ｘ射线光电子能谱仪、等离子耦合光谱、Ｘ射线衍射仪以及俄歇能谱仪等现代微观分析手段，探讨了Ｃｅ微合金化对Ｆｅ３Ａｌ合金组织结构和力学性能影响的作用机制。研究结果表明，Ｃｅ的加入改善了合金的室温塑性和强度，并在合金中起到了脱硫、脱氧、改变夹杂物形态、细化晶粒以及表面改性等作用。此外还对富Ｃｅ相颗粒在合金中的形态分布作了分析。     

铈对2090铝锂合金织构和力学性能的影响

为了解Ｃｅ对铝锂合金力学性能各向异性的影响,对不同Ｃｅ含量２０９０铝锂合金织构进行了ＯＤＦ（取向分布函数）测算,对合金不同方向性能进行了测量,分析了Ｃｅ对合金 构和力学性能的影响。２０９０铝锂合金主织构类型为（２２５〈５５４〉,Ｃｅ不改变合金主织构类型,但造成主织构类型分布漫散;由于Ｃｅ降低了蛔屈服强度各向异性织构成分的含量,故Ｃｅ可改变２０００铝锂合金理想织构成分的体积分数,减小屈服强度各向异性     

Microstructural and Mechanical Properties of Al-20%Si Containing Cerium

In this paper the effect of cerium addition in hypereutectic Al-Si alloys was studied. Casting method was used to produce Al-20Si with variation of Ce contents. The sample characterization studied was investigated by Optical Microscope, X-ray fluorescence and X-ray Diffraction. Vickers microhardness and wear test was carried out to study the influence of Ce towards the Al-20Si alloys. The addition of Ce in the Al-20Si alloys refined the Si primary phase as the Ce content increases. The results showed that the addition of 0.46 to 2.24 wt.% of cerium in Al-20Si alloys led to the formation of fine cells dispersed in the Al-matrix. These fine cells consist of a mixture of eutectic Si particles and intermetallic Al3Ce and CeAl1.2Si0.8 phase in Al matrix. The amount of rod- like intermetallic Al3Ce and CeAl1.2Si0.8 phase increases with increasing Ce content. The microhardness of Al-20Si alloys increases with the increase in Ce content. Addition of Ce up to 1.61 wt.% Ce improve the wear properties of Al-20Si alloy.     

二元氯化物熔体中锂和钠离子析出电位的测定及去极化作用的研 究

本文利用I-V曲线法测定了锂和钠离子在二元混合氯化物体系(LiCl-KCl;NaCl-KCl)中的析出电位,为利用熔盐电解法制备低钠高纯铝-锂合金提供了理论依据。根据锂离子在铝阴极上产生的去极化值求出铝和锂发生合金化反应的热力学意义,提出二元合金类型与极化类型之间的经验关系。首次通过研究锂离子在铝合金电极上的去极化行为,发现某些第三合金元素的存在可以加强锂离子的去极化作用,为进一步制取低钠高纯三元铝-锂-M合金系列提供了参考。还研究了在氯化钾-氯化锂体系中,氯化锂浓度对锂离子在铝阴极上析出电位的影响,求出了氯化锂的平均活度系数。     

Spectrophotometric determination of cerium(IV) using a phenothiazine derivative.

A simple, rapid and sensitive spectrophotometric method has been proposed for the determination of cerium(IV) using a phenothiazine derivative, propionyl promazine phosphate (PPP). This method is based on the formation of a red-colored radical cation upon a reaction of PPP with cerium(IV) in a phosphoric acid medium having maximum absorbance at 513 nm. Beer's law is valid over the concentration range of 1-11 microg/ml with a Sandell's sensitivity value of 16.14 ng/cm2. The proposed method has been successfully applied to the analysis of magnesium-base cerium alloys and synthetic mixtures corresponding to various cerium alloys. Other phenothiazine derivatives viz. butaperazine dimaleate and propericiazine were also used for the determination of cerium(IV).     

熔盐热腐蚀的电化学交流阻抗谱研究

采用电化学阻抗谱技术研究了Ｎｉ３Ａｌ、ＩＮ１００和ＩＮ７３８合金在７００℃熔融（Ｎａ,Ｋ,Ｌｉ）２ＳＯ４中的腐蚀行为．结果表明,Ｎｉ３Ａｌ和ＩＮ１００合金的腐蚀呈典型的扩散控制特征,在合金表面形成疏松的腐蚀层;而ＩＮ７３８合金因在表面形成保护性的Ｃｒ２Ｏ３膜,腐蚀不受扩散控制．提出了等效电路并计算了相应的电化学参数．     

Interaction of Ca,P trace elements and Sr modification in AlSi5Cu1Mg alloys

Thermal and microscopy analyses were carried out to investigate the interaction of Sr modification with Ca and P trace elements in high-purity and commercial-purity Al–5Si–1Cu–Mg alloys. The results show how the addition of Sr to commercial-purity alloy induces significant changes in the nucleation and growth temperatures of eutectic Si since pre-eutectic Al₂Si₂(CaSr) intermetallics tend to poison AlP particles, making them inactive as nucleation sites for eutectic Si. In contrast, the addition of Sr to high-purity alloy shows no apparent influence on the characteristic temperatures of Al–Si eutectic reaction, even though the microstructural investigations reveal flake-to-fibrous transition in the eutectic Si structure. This indicates that the eutectic growth temperature, commonly used to predict eutectic modification level, is not a key feature of Sr modification, but it is indirectly caused due to the presence of additional impurities in commercial-purity alloys which affect the nucleation kinetics of eutectic Si.     

Magnesium–lithium alloys with TiB and Sr additions

The ultralight hypoeutectic α-phase Mg–4.5Li–1.5Al alloy and hypereutectic β-phase Mg–12Li–1.5Al alloy in as-cast state were fabricated and subjected to modification by 0.2 mass% TiB and 0.2 mass% Sr grain modifiers. The crystallisation sequence of Mg–Li–Al alloys has been investigated in detail by using thermal-derivative analysis and microstructural observations. The presented work includes the effects of grain refiners on grain size and microstructure and thermal events registered during crystallisation of ultralight Mg–Li–Al alloys by recording and analysis of the temperature vs time, i.e. as T_N, T_α, T_β, T_η(LiAl) and T_SOL. Microstructure and phase observation has been done by light microscope, X-ray diffraction and energy dispersive X-ray spectroscopy. The changes of characteristic temperature points for phase transformation are studied in detail. Due to the addition of 0.2 mass% TiB and 0.2 mass% Sr, the grain structure of the alloy was refined, and mechanical properties were improved. When a TiB and Sr added simultaneously, the average grain size of the analysed alloys strongly decreases. When the TiB or Sr content was severally added, a low effect of improvements of mechanical properties was observed. With the TiB and Sr content, the liquidus and solidus decrease gradually.

     

样品基体化学改进剂-石墨炉原子吸收光谱法测定镍合金中痕量铋

镍基合金是航空工业的重要金属材料,合金中铋、铅、锡等易挥发元素的含量对合金材料性能影响很大[1,2].原子光谱法常被用于分析镍基合金中的痕量元素,如火焰原子吸收光谱法(FAAS)、氢化物发生-原子吸收(荧光)光谱法(HG-AAS/AFS) [3]、电感耦合等离子体-质谱法(ICP-MS).     

Development of ion chromatography and capillary electrophoresis methods for the determination of Li in Li–Al alloy

Two methods were developed for determination Li content in Li–Al alloy by employing ion chromatography (IC) and capillary electrophoresis (CE) without any prior separation of Al matrix. In absence of suitable certified reference material the two methods were used to validate each other. Using a high capacity column and a weaker eluent methane sulphonic acid, it was possible to separate Li in IC without eluting strongly retained Al. The method showed good precision and sensitivity and was extended for analysis of routine samples. In the case of CE using imidazole as co-ion, Li was detected in CE by indirect detection. In view of no interference from Al, samples were analyzed without any matrix separation. The CE method was used successfully for sample analysis and results were compared with IC results.