Nb_6Sn_5生成Nb_3Sn的生长特性

采用Nb管富Sn固-液相扩散法,研究了Nb_6Sn_5向Nb_3Sn转化过程中Sn的扩散方式及微组织结构.实验结果表明:Nb_3Sn层生长受Nb_6Sn_5分解时Sn的短程扩散和长程扩散两种机制的控制,分别形成晶粒较粗的内层和晶粒较细的外层;粗细晶粒的差别和热处理温度有关.根据此机制得出的扩散方程解与Nb_3Sn生长曲线符合得很好.     

INFLUENCE OF GEOMETRICAL CONFIGURATION OFSUPERCONDUCTING MATERIAL ON GROWTH OF Nb_3 Sn

Boundary conditions constructed by two typical geometrical configurations related to themanufacturing methods of bronze process and tin-rich Nb tube method have been consideredin a diffusion model in which the diffusion of Sn in CuSn matrix plays a major role is as-sumed.The dependence of thickness of Nb_3Sn layer on reaction time has been derived.It isshown that the growth rate of Nb_3Sn relates to the configuration of the superconductor,thegeometrical parameters of Nb filaments and CuSn matrix.The theory is qualitatively con-sistent with the experimental results.     

超导材料的几何构形对Nb_3Sn扩散生长的影响

采用体扩散模型,假定Sn在CuSn母体中的扩散是Nb_3Sn层生长的控制因素,考虑了青铜法和Nb管富Sn法这两种典型的成材方法的几何构形所形成的边界条件,在一级近似下解出了Nb_3Sn层厚度和热处理时间的依赖关系。结果表明:Nb_3Sn层生长速率与超导材料的复合构形、Nb纤维以及CuSn母体的几何参数有内在联系。理论与实验结果定性相符。     

内扩散法Nb3Sn多芯线材的磁化特性研究

研究了内扩散法Ｎｂ３Ｓｎ多芯线材随温度和磁场变化的磁化曲线及磁化率,绘出了磁化量－磁场－温度（Ｍ－Ｈ－Ｔ）的三维临界曲面,归一化后的磁化曲线基本符合Ｋｒａｍｅｒ拟和方程。计算得到的Ｎｂ３Ｓｎ多芯线材有效直径比芯线的原始几何尺寸要大,其原因在于微观结构中存在着“桥梁”,分析表明,多余的磁滞损耗来自于“桥梁”。交流磁化率和Ｘ’和Ｘ″在给定频率和背景磁场下,随交流振幅的变化很小,在给定交流振幅下,随交流     

INTERACTION BETWEEN Cu AND LIQUID Sn(II)——SEM OBSERVATION OF INTERMETALLIC GROWTH

The features of Cu_6Sn_5 growing slowly at lower temperature and growing rapidly up over350℃,and or Cu_3Sn growing at higher temperatures,bave been detailedly observedunder SEM.The increase of Pb content seems to inhibit sequentially the growth ofCu_6Sn_5 in Pb-Sn alloy.     

X-RAY POWDER DIFFRACTION DATA AND STRUCTURAL REFINEMENT OF Er_3Co_6Sn_5

１ＩＮＴＲＯＤＵＣＴＩＯＮＲａｒｅｍｅｔａｌｓａｎｄｔｈｅｉｒｃｏｍｐｏｕｎｄｓｈａｖｅｏｕｔｓｔａｎｄｉｎｇｐｒｏｐｅｒｔｉｅｓａｎｄａｒｅｐａｉｄｉｎｃｒｅａｓｉｎｇａｔｅｎｔｉｏｎｔｏ．Ｎｕｍｅｒｏｕｓｉｎｖｅｓｔｉｇａｔｉｏｎｓｉｎｔｈｅ...     

Nb_2O_5-MnO-SiO_2渣中Nb_2O_5和MnO活度的研究SCIEI

本文利用含NbFe液与Nb_2O_5-MnO-SiO_2渣之间平衡,在1828K温度下应用固体电解质浓差电池方法测定了Fe液中氧的活度,从而计算出渣中Nb_2O_5及MnO的活度,并绘制了Nb_2O_5-MnO-SiO_2三元系的等α_(Nb_2O_5)和等α_(MnO)图。     

微连接用Sn-2.5Ag-0.7Cu(0.1RE)钎料焊点界面Cu6Sn5的长大行为

利用XRD、SEM及EDAX研究了钎焊和时效过程中低银Sn-2.5Ag-0.7Cu(0.1RE)/Cu焊点界面区显微组织和Cu6Sn5金属间化合物的生长行为。结果表明,钎焊过程中焊点界面区Cu6Sn5金属间化合物的厚度是溶解和生长两方面共同作用的结果;随时效时间的增加,焊点界面区Cu6Sn5的形貌由扇贝状转变为层状,其长大动力学符合抛物线规律,由扩散机制控制;添加0.1%(质量分数,下同)的RE能有效减慢界面Cu6Sn5金属间化合物在钎焊及时效过程中的长大速度,改变焊点的断裂机制,提高其可靠性。     

Cu 5Ni 4Sn 3Al合金的时效强化

根据合金的力学和电学性能, 利用ＸＲＤ,ＴＥＭ 和ＳＥＭ 技术研究了Ｃｕ５Ｎｉ４Ｓｎ３Ａｌ 合金的时效强化。结果表明：３５０ ℃下时效时, 力学性能增加; 边带分析有边带效应, 且随时效时间的增加调幅波长增加。电镜下观察到调幅结构, 说明该合金是调幅分解强化的合金。同时, 铝的加入没有改变合金的相结构, 但是, 对合金的强化起着重要作用。实验结果还表明, 合金在时效过程中, 调幅分解的同时还形成ＤＯ２２（ＴｉＡｌ３） 型结构的Ｎｉ３Ｓｎ 化合物相     

SPS熔铸制备Nb/Nb_5Si_3原位复合材料

利用SPS熔铸工艺成功制备了近理论密度的Nb/Nb5Si3原位复合材料,并用XRD、扫描电镜(SEM)、电子探针微区分析(EPMA)和电子能谱分析(EDS)研究复合材料的相组成和微观结构。结果表明,SPS熔铸的Nb/Nb5Si3复合材料组织由近球状的初生Nb颗粒与(Nb+Nb5Si3)共晶组织组成,且随着冷却速度增加,复合材料组织中的初生Nb颗粒和共晶组织变得细小。SPS熔铸工艺可同步实现Nb/Nb5Si3复合材料的原位合成与液态成形一体化,所制备Nb/Nb5Si3原位复合材料的密度达到理论密度的99.69%。     

低温超导体Nb_3Sn扩散热处理中显微组织的表征与分析

利用青铜法制备了低温超导体Nb3Sn材料。采用X射线衍射(XRD),扫描电镜(SEM)和能谱(EDS)对Nb3Sn化合物的元素扩散热处理过程进行了研究。结果显示,通过热处理96h后,Nb3Sn相形成。同时由于边界处Nb原子的缺乏,Nb2Sn和Nb6Sn5非超导相也在边界处形成。升高温度明显能够提高元素的扩散激活能,从而利于Nb3Sn相的形成,但是高温也会促进晶粒的粗化,破坏超导特性。因此精确控制温度对于材料超导性能非常重要。采用670℃热处理96h得到了均匀细小的晶粒组织。     

偏量应变定标模型在Nb_3Sn股线中的应用

采用Pacman弹簧装置测量在不同磁场,温度和应变条件下Nb3Sn多芯股线的V-I特征曲线。外部磁场变化范围由4T到14T,温度变化由4.2K至10K,材料轴向应变变化范围在-0.9%～+0.6%。在此基础上详细介绍了近年来应用广泛的三维偏量应变定标模型,通过该定标模型模拟了Nb3Sn超导材料临界电流Ic随应变状态的变化规律。     

PROCESSING AND PROPERTIES OF Nb_3Al ALLOYS

ＰＲＯＣＥＳＳＩＮＧＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＮｂ_３ＡｌＡＬＬＯＹＳＨＡＮＡＤＡＳｈｕｊｉ；ＴＡＢＡＲＵＴａｔｓｕｏａｎｄＧＮＭＡＭＯＯＲＴＨＹＲａｊａｐｐａ（ＩｎｓｔｉｔｕｔｅｆｏｒＭａｔｅｒｉａｌｓＲｅｓｅａｒｃｈ，ＴｏｈｏｋｕＵｎｉｖｅｒ?..     

Ultrafine eutectic Ti x Sn y /TiNi composites with high damping capacity

Three kinds of bulk-type ultrafine Ti _x Sn _y /TiNi (Ti _x Sn _y represents Ti₃Sn, Ti₂Sn, and Ti₅Sn₃ or Ti₆Sn₅) composites with homogeneous eutectic microstructure were prepared by arc melting. The composites exhibit high damping capacity (tanδ greater than 1 × 10^?2) and enhanced mechanical strength (the highest fracture strength is 2.15 GPa). The damping capacity originates from TiNi and Ti₃Sn, while the eutectic contributes to the mechanical strength.     

INTERACTION BETWEEN Cu AND LIQUID Sn (Ⅱ) SEM Observation of Intermetallic Growth

用扫描电镜(SEM)研究了Cu与液态Sn的相互作用。观察到了350℃时Cu_6Sn_5的生长突跃和Sn层中化合物生长的形态。以及Sn-Pb合金中随Pb含量增加Cu_6Sn_5生长趋势减弱。     

Cu与液态Sn的相互作用(Ⅱ)——金属间化合物生长的SEM观察

用扫描电镜(SEM)研究了Cu与液态Sn的相互作用。观察到了350℃时Cu_6Sn_5的生长突跃和Sn层中化合物生长的形态。以及Sn-Pb合金中随Pb含量增加Cu_6Sn_5生长趋势减弱。     

Optical Constant and Electrical Resistivity of Annealed Sn_3Sb_2S_6 Thin Films

In this study,we report the annealing effects on the physical properties of Sn_3Sb_2S_6 thin films.Sn_3Sb_2S_6 thin films were prepared onto non-heated glass substrates via thermal evaporation technique.The as-deposited films were annealed in air for 1 h in the temperature range from 100 to 300 °C.X-ray diffraction results show that the crystallinity of the thin films increased after annealing.The microstructure parameters crystallite size,dislocation density,lattice strain and stacking fault probability were calculated.The optical properties were obtained from the analysis of the experimental recorded transmittance and reflectance spectral data over the wavelength range 300–1800 nm.High absorption coefficient(10~5cm~(-1)) reached to the visible and near-IR spectral range.A decrease in optical band gap from 1.92 to 1.71 e V by increasing the air annealing temperature was observed.Oscillator energy E_o and dispersion energy E_d of the films after annealing were estimated according to the model of Wemple–Di Domenico single oscillator.Spitzer–Fan model was applied to determine the electron free carrier susceptibility and the ratio of carrier concentration to the effective mass.The layers annealed at temperatures 150 ℃ undergo abrupt changes in their electrical properties and exhibit a resistive hysteresis behavior.These properties confer to the material interest perspectives for its application in diverse advanced technologies such as photovoltaic applications and optical storage.     

Effects of calcium addition on as-cast microstructure and mechanical properties of Mg-5Zn-5Sn alloy

The effects of Ca addition on the as-cast microstructure and mechanical properties of the Mg-5Zn-5Sn (mass fraction,%) alloy were investigated.The results indicate that an addition of 0.5%-1.5% (mass fraction) Ca to the Mg-5Zn-5Sn alloy not only refines the as-cast microstructure of the alloy but also causes the formation of the primary and/or eutectic CaMgSn phases with high thermal stability;an increase in Ca amount from 0.5% to 1.5% (mass fraction) increases the amount and size of the CaMgSn phase.In addition,Ca addition to the Mg-5Zn-5Sn alloy improves not only the tensile properties at room temperature and 150 ℃ but also the creep properties.Among the Ca-containing Mg-5Zn-5Sn alloys,the one added 0.5% (mass fraction) Ca obtains the optimum ultimate tensile strength and elongation at room temperature and 150 ℃,however,the alloy added 1.5% (mass fraction) Ca exhibits the optimum yield strength and creep properties.     

(Mn1-xFex)5Sn3合金晶体结构和居里温度

用粉末冶金法(磁场压制烧结)制备(Mn1-xFex)5Sn3(x=0.1～0.5)合金,对其晶体结构、居里温度进行研究。室温XRD分析表明,该系列合金均保持Mn5Sn3的InNi2型相结构,计算发现合金的晶格常数随着x量增大而减小。通过M-T曲线测量结果表明:居里温度TC在室温附近244～391K连续可调,且随着Fe含量的增加而提高,居里温度随成分近似呈线性变化;成分为(Mn0.70Fe0.30)5Sn3合金的居里温度为295K,在外加磁场为0～1.5T下,最大磁熵变约为0.87J·(kg·K)-1,是一种成本低廉的室温磁制冷候选材料。     

粉末冶金Ti-5Al-2.5Sn ELI合金显微组织研究

采用包套热等静压工艺制备了粉末冶金Ti-5Al-2.5Sn ELI(extra low interstitial)合金,研究了热等静压温度、粉末粒度、后续热处理温度对合金显微组织的影响。当热等静压温度在800℃时,粉末体压坯显微组织保持颗粒形态,致密度为99.2%;当温度在900~940℃时,显微组织演变为完全致密、细小的等轴晶。在α相区热等静压温度下,包套中的Fe在基体中的扩散不明显;在α+β、β相区温度下,Fe在β相中向基体快速扩散,影响合金表面质量。粉末粒度越大,合金的平均晶粒尺寸越大,残留孔隙较多。在α相区热处理,显微组织仍为细小等轴晶;当温度升至1000℃时,出现热致孔隙。