Cu—Zn—Al合金中贝氏体的扫描隧道显微镜分析

本文用扫描隧道显微镜（ＳＴＭ）在大气中研究了Ｃｕ－２７．２ｗｔ．％Ｚｎ－４．７ｗｔ．％Ａｌ合金中的贝氏体的精细结构，并与透射电镜（ＴＥＭ）及扫描电镜（ＳＥＭ）下的形态进行了比较，发现Ｃｕ－Ｚｎ－Ａｌ合金中虫氏体是由亚片条或亚单元组成，亚单元由超亚单元构成，进而为贝氏相变机制的再认识提供了重要的实验基础，并在此基础上提出Ｃｕ－Ｚｎ－Ａｌ合金中贝氏体的形成模型。     

关于Cu－Zn－Al贝氏体相变的阶段性──亚结构与体转变激活能

从Ｃｕ－Ｚｎ－Ａｌ合金相变产物的形貌与亚结构的特征着手分析了贝氏体相变的阶段性。测定了贝氏体相变阶段的体转变激活能并讨论了贝氏体相变的性质。     

关于Cu—Zn—Al贝氏体相变的阶段性—亚结构与体转变激活能

从Ｃｕ－Ｚｎ－Ａｌ合金相变产物的形貌与亚结构的特征着手分析了贝氏体相变的阶段性。测定了贝氏体相变阶段的体转变激活能并讨论了贝氏体相变的性质。     

Cu－Zn－Al合金贝氏体的三个生长阶段及其精细结构研究

利用透射镜研究了Ｃｕ－Ｚｎ－Ａｌ合金贝氏体ａ＿１相在相变过程中的精细结构变化，发现贝氏体的生长经历三个阶段：初生态、中间态和退化态。初生贝氏体内不含层错亚结构，ａ＿１依台阶机制长大到一定程度后，内部出现层错；随转变进一步进行，ａ＿１内的层错结构逐渐消失，发生“过退火”，最终向平衡相转变。     

FeCrAl合金中碳化物的时效析出和钇的影响

ＴＥＭ研究表明,低碳（０．０１－０．０３ｗｔ．％Ｃ）Ｆｅ－（１５．２５）Ｃｒ－（４,５）Ａｌ合金经１２００℃固溶处理后再于４７５－５４０℃时效时,碳化物迅速在晶界、位错等昌体缺陷处析出,晶界碳化物近于连续,晶界两侧形成析出带,析出相的衍谱与Ｃｒ２３Ｃ６和Ｃｒ７Ｃ３基本吻合,在含０．４ｗｔ．％Ｙ的ＦｅＣｒＡｌ合金中,含２相的衍射谱与六方α－Ｆｅ１７Ｙ２相的谱吻合,该相俘获碳原子的作用使合金在时效时不     

SiCw／Al－Li复合材料中界面无析出带的TEM观察

ＳｉＣｗ／Ａｌ－Ｌｉ复合材料中界面无析出带的ＴＥＭ观察董尚利，崔约贤，茅建富，来忠红，杨德庄（哈尔滨工业大学材料科学与工程学院，哈尔滨１５０００１）本文采用透射电镜选区电子衍射技术和暗场技术，研究了压铸法制备的１５Ｖｏｌ％ＳｉＣｗ／Ａｌ－２．１８ｗｔ...     

Au—Sn合金电镀

概述了改善的Ａｕ－Ｓｎ合金镀液,可以稳定地形成组成为８０ｗｔ％Ａｕ,２０ｗｔ％Ｓｎ的Ａｕ－Ｓｎ合金镀层,适用于具有抗蚀剂图形的半导体等电子零件上形成Ａｕ－Ｚｎ合金微细焊料图形。     

Cu－Zn－Al合金预贝氏体相变与贝氏体形核研究

本文考察了Ｃｕ－Ｚｎ－Ａｌ合金的预贝氏体相变与贝氏体形核。内耗实验表明预贝氏体相变的主要过程为溶质原子扩散、偏聚；能谱分析揭示预贝氏体相变时存在溶质偏聚引起的溶质原子贫化区与富化区；原位观察证实贝氏体于溶质原子贫化区切变形核。     

MIS（Au－SiO_2－Si）隧道发光结

在研究一般ＭＩＭ（Ａｌ－Ａｌ２Ｏ３－Ａｕ）结的基础上，为了克服Ａｌ的不稳定性和改善结的性能，我们采用半导体材料Ｓｉ代替Ａｌ，研制成功ＭＩＳ（Ａｕ－ＳｉＯ２－Ｓｉ）隧道结，观察到了稳定的发光现象．介绍了ＭＩＳ结的基本结构和工艺流程，分析了结中ＳＰＰ的各个模式，讨论了结的发光光谱，阐明了ＭＩＳ结的发光机理．     

Cu─Zn─Al贝氏体及贝氏体／母相界面的精细结构

利用高分辨电镜考察了Ｃｕ－Ｚｎ－Ａｌ合金中不同生长时间的贝氏体及贝氏体／母相界面的精细结构；分析、讨论了贝氏体的有序性、贝氏体／母相界面点阵的共格性及贝氏体前沿母相中的微应变衬度。试验结果支持贝氏体相变的切变机制。     

High-reliability interconnections for ULSI using Al-Si-Pd-Nd/Molayered films

An Al-Si-Pd-Nb alloy and a bilayered interconnection using this alloy with molybdenum have been investigated for ULSI interconnections. The electromigration lifetime of Al-Si-0.3 wt.% Pd-0.4 wt.% Nb was 5 times better as compared to Al-Si-0.5 wt.% Cu. In addition, layering this alloy with low-resistivity molybdenum improved the electromigration resistance considerably as compared to Al-Si-Cu layered with a high-resistivity metal, i.e., TiW. PdO was thought to be formed on the Al-Si-0.3 wt.% Pd-0.4 wt.% Nb alloy's surface. The corrosion resistance of this alloy is much better than that of Al-Si-Cu because of this PdO. The ease in patterning the alloy at submicrometer linewidths (to 0.5 μm) is quite satisfactory. The Al-Si-Pd-Nb/Mo layered system is therefore thought to be promising for future interconnection applications requiring durability against high current densities     

A comparative analysis of microstructural features,tensile properties and wettability of hypoperitectic and peritectic Sn-Sb solder alloys

Sn-Sb alloys are among the current alternatives for the development of alloys for high-temperature lead-free solders. The Sn-Sb alloys having 5.5 wt.% Sb or less are known to have good mechanical properties, and despite the quite low liquidus temperature have been considered adequate in the development of solder joints. The increase in the Sb content up to the limit of solubility in Sn at about 10 wt.% is supposed to be detrimental to the mechanical properties due to the extensive formation of an intermetallic compound. Investigations on the interrelation of microstructure of this alloy and the corresponding mechanical properties are fundamental to an appropriate evaluation of its application in solder joints. The present investigation analyses the relationship between microstructural features of the peritectic Sn-10 wt.% Sb alloy, solidified under a wide range of cooling rates, and the resulting mechanical properties. A cellular β-Sn matrix, typified by cellular spacings that decrease with the increase in the solidification cooling rate, and Sn₃Sb₂ particles are shown to characterize the alloy microstructure. The ultimate tensile strength is higher as compared with the corresponding values of the hypoperitectic Sn-5.5 wt.% Sb solder alloy, however the elongation is shown to decrease. A comparison with Bi-Ag alloys, considered good high temperature solders alternatives, has shown that the tensile properties of the Sn-10 wt.% Sb alloy, including elongation, are significantly higher. Wettability tests have been carried out and the experimental results, according to reports from the literature, are associated with good wettability.     

Experimental investigation of Ge-doped Bi-11Ag as a new Pb-free solder alloy for power die attachment

A bismuth-silver alloy (Bi-11wt.%Ag) has been identified as a viable Pb-free power die-attach solder. The alloy has a solidus at 262.5°C and a liquidus at 360°C. It has a shear modulus of 13.28 GPa and an ultimate tensile strength (UTS) of 59 MPa. Bismuth-silver alloys oxidize in air but will solder to nickel, silver, and gold under reducing atmospheres. Germanium may be added in small amounts (≤500 ppm) to improve the wetting. Wire, ribbon, and preform shapes of the alloy have been fabricated by conventional metalworking techniques.     

Creep deformation of Sn-3.5Ag-xCu and Sn-3.5Ag-xBi solder joints

Creep properties of lead-free Sn-3.5Ag-based alloys with varying amounts of Cu or Bi were studied by single lap-shear test. Solder balls with five different compositions of Cu (0 wt.%, 0.75 wt.%, 1.5 wt.%) and Bi (2.5 wt.%, 7.5 wt.%) were reflowed on Cu. The Cu-containing alloy had a lower creep rate than the Bi-containing alloy. The Sn-3.5Ag alloy showed the lowest creep rate on Cu, implying that the Cu element already dissolved in the Sn-3.5Ag alloy during reflow. The Cu-containing alloy was strengthened by dispersed small precipitates of Cu₆Sn₅. As the Cu content increased up to 1.5 wt.%, the Cu₆Sn₅ coarsened and platelike Ag₃Sn intermetallics were found, which deteriorated the creep resistance.     

Wetting Behavior and Mechanical Properties of Sn-Zn and Sn-Pb Solder Alloys

A comparative experimental study of the main features of the eutectic Sn-Pb alloy and Sn-Zn alloys was carried out with a view to application of the latter alloys as alternative solder materials. The resulting microstructures, mechanical properties (ultimate tensile strength and elongation), and wettability behavior (spreading area and contact angle) of a hypoeutectic Sn-Zn (Sn-4wt.%Zn), a hypereutectic Sn-Zn (Sn-12wt.%Zn), and the eutectic Sn-9wt.%Zn alloy were examined and compared with the corresponding results of the conventional Sn-40wt.%Pb solder alloy. It was found that, of the Sn-Zn alloys examined, the eutectic Sn-9wt.%Zn alloy offers a compromise between lower wettability and higher mechanical strength.     

Microstructure and Tensile Properties of Sn-1Ag-0.5Cu Solder Alloy Bearing Al for Electronics Applications

This work investigates the effects of 0.1?wt.% and 0.5?wt.% Al additions on bulk alloy microstructure and tensile properties as well as on the thermal behavior of Sn-1Ag-0.5Cu (SAC105) lead-free solder alloy. The addition of 0.1?wt.% Al reduces the amount of Ag₃Sn intermetallic compound (IMC) particles and leads to the formation of larger ternary Sn-Ag-Al IMC particles. However, the addition of 0.5?wt.% Al suppresses the formation of Ag₃Sn IMC particles and leads to a large amount of fine Al-Ag IMC particles. Moreover, both 0.1?wt.% and 0.5?wt.% Al additions suppress the formation of Cu₆Sn₅ IMC particles and lead to the formation of larger Al-Cu IMC particles. The 0.1?wt.% Al-added solder shows a microstructure with coarse ??-Sn dendrites. However, the addition of 0.5?wt.% Al has a great effect on suppressing the undercooling and refinement of the ??-Sn dendrites. In addition to coarse ??-Sn dendrites, the formation of large Sn-Ag-Al and Al-Cu IMC particles significantly reduces the elastic modulus and yield strength for the SAC105 alloy containing 0.1?wt.% Al. On the other hand, the fine ??-Sn dendrite and the second-phase dispersion strengthening mechanism through the formation of fine Al-Ag IMC particles significantly increases the elastic modulus and yield strength of the SAC105 alloy containing 0.5?wt.% Al. Moreover, both 0.1?wt.% and 0.5?wt.% Al additions worsen the elongation. However, the reduction in elongation is much stronger, and brittle fracture occurs instead of ductile fracture, with 0.5?wt.% Al addition. The two additions of Al increase both solidus and liquidus temperatures. With 0.5?wt.% Al addition the pasty range is significantly reduced and the differential scanning calorimetry (DSC) endotherm curve gradually shifts from a dual to a single endothermic peak.     

Mg-Al-Zn-Sn合金时效析出的γ相颗粒数密度的测定

Mg-9.0wt.%Al-1.0wt.%Zn-4.0wt.%Sn合金样品在523 K温度下时效后,析出大量γ-Mg17Al12颗粒。利用会聚束电子衍射的方法测量样品的厚度,进而计算γ相颗粒的数密度Nv。结果表明在Mg-9.0wt.%Al-1.0wt.%Zn-0.2wt.%Mn合金中,添加一定量的Sn元素后促进了γ-Mg17Al12相颗粒的析出。     

Corrosion resistance of Al-Pd-Si conductor

An Al-Pd-Si alloy conductor which has higher corrosion resistance than an Al-Si conductor after resin molding is discussed. A palladium oxide-rich (PdO-rich) area is formed by annealing in the surface oxide film on the Al-Pd-Si alloy conductors. It is responsible for the increased corrosion resistance of Al-Pd-Si with over 0.3 wt.% Pd     

Lowering of Sn−Sb alloy melting points caused by substrate dissolution

Sn−5wt.%Sb alloy is used for the soldering of ceramic devices. Reaction couples, dissolution, and differential scanning calorimetry experiments are conducted to examine the interfacial reactions and dissolution of Ag substrates with the molten Sn−5wt.%Sb solder. One intermetallic compound, Ag₃Sn, is formed at 260°C at the Sn−5wt.%Sb/Ag contact. With the intake of Ag from the substrate, the binary Sn−5wt.%Sb alloy becomes a ternary (Sn−5wt.%Sb)_100−xAg_x melt. It is found that a small amount of Ag addition significantly lowers the melting point of the Sn−5wt.%Sb alloy. This phenomenon is illustrated with the (Sn−5wt.%Sb)_100−xAg_x isoplethal section.