添加尖晶石对氧化锌压敏电阻性能的影响

通过添加尖晶石（Ｚｎ７Ｓｂ２Ｏ（１２））改性研制出电位梯度为１００Ｖ／ｍｍ左右，压敏电压在８２～１５０Ｖ，通流容量可达１６００Ａ／ｃｍ２，漏电流＜２μＡ系列压敏电阻器，从而满足了国内电话交换机行业对８２Ｖ、１００Ｖ、１２０Ｖ、１５０Ｖ压敏电阻器的电性能要求。从工艺的角度解释了尖晶石对氧化锌瓷晶粒的作用原理，并分析了尖晶石的微观结构及粒度对瓷片电性能的影响。     

激光辐照40Cr钢组织结构的穆斯堡尔谱分析

４０Ｃｒ钢试样经不同热处理后在空气中用ＣＯ２连续激光束进行辐照，以穆斯堡尔谱学研究试样在辐照后的组织结构变化。试验结果表明，调质预处理后再进行激光辐照的试样，不仅残作产奥氏体含量较低，而且其中碳的含量最低。     

定向结晶时高温合金组织控制的工艺前景EI

报道了俄国航空材料研究院(ВИАМ)在定向单晶高温合金组织控制方面的最新研究成果,例如,利用高速定向结晶工艺创造具有单晶组织的宽弦叶片,以及制造前后缘为规定位相的单晶,而在叶身中部为细柱状定向结晶组织的复合组织叶片。这些新工艺提高了材料的工作能力和发动机寿命。     

Contact interaction of double titanium and chromium diboride with Fe-Cr alloys

The kinetics of wetting double titanium and chromium diboride by iron-based alloys with different chromium content is studied. It is shown that contact angles are formed in such systems over the range 0–10°. The energy parameters of wetting are calculated. It is established that chromium as a surface-active element promotes Fe-Cr alloy spreading on the diboride surface. The microstructure of the interaction area is studied. It is shown that terminal solid solutions and eutectics are formed in the TiCrB₂-(Fe-Cr) system. The optimum compositions of the metallic binder are determined for TiCrB₂-based composite materials. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 1–2(453), pp. 109–115, 2007     

20CrMo棒材带状组织的控制研究

通过Gleeble-1500热模拟机对20CrMo轧材精轧阶段轧制过程及冷却过程的模拟,研究了终轧温度、冷却速度对室温组织的影响,分析了形成带状组织的条件,最终得出了理想室温组织的终轧温度和冷却速度。     

钻井工程固井胶结界面研究现状

固井质量问题在石油勘探开发中备受关注，对特殊工艺井钻井、油水井开采寿命和勘探开发效益有直接的影响。对固井胶结界面的研究是从根本上提高固井质量的一项基础性研究工作。为了推动固井胶结界面研究工作的开展，分析了国内外近年来有关固井界面研究的文献，阐述了开展固井胶结界面基础研究工作的意义，着重分析了这一研究领域目前所采用的研究方法，以及提高固井界面胶结强度的主要途径。在分析文献的基础上，提出今后深入开展固井界面研究工作的重点是：1）继续完善研究方法；2）重视动态研究；3）从胶结界面的微观结构和钻井工程整体系统的角度开展研究工作；4）注重改善胶结界面水化产物的微观结构和钻井工作液之间的协调增强作用。     

添加高速钢粉对烧结钢组织与性能的影响

研究了添加高速钢粉对烧结钢组织与性能的影响。实验结果表明，含２０％高速钢的烧结钢综合力学性能最好；添加高速钢粉能导致烧结钢密度减小的冲击韧性降低，当高速钢含量增中时，硬度随之增加，烧结钢中残余奥氏体和马氏体的含量与高速钢的含量呈线性关系。烧结钢中的马氏体显微硬度很高，它主要原高速钢粒子和原铁粒子的连接区域形成。     

Comparison of interfaces in Ti composites reinforced with uncoated and TiB2/C-coated SiC fibres

Interfaces play an important role in determining the mechanical properties of composite materials. The interfaces established between a titanium-alloy matrix (Ti-6Al-4V) and uncoated and TiB₂/C-coated SiC fibres are analysed by scanning electron microscopy, transmission electron microscopy and X-ray techniques. Emphasis is placed upon the interfacial morphology and microstructure, identification of reaction products, and the stability of the coating layer. Complex multi-reaction layers are observed frequently in the interfacial zones. Previous, often contradictory, reports about the interlayers are reviewed. Experimental observation demonstrates that the type and distribution of interlayers vary in a given system, due to prolonged treatment of the samples at temperature. The formation and distribution of the interlayers are discussed further, with respect to these and previous findings. Methods of reducing interfacial reactivity are discussed.     

Material flow and microstructure in the friction stir butt welds of the same and dissimilar aluminum alloys

The material flow and microstructural evolution in the friction stir welds of a 6061-Al alloy to itself and of a 6061-Al alloy to 2024-Al alloy plates of 12.7 mm in thickness were studied under different welding conditions. The results showed that plastic deformation, flow, and mechanical mixing of the material exhibit distinct asymmetry characteristics at both sides of the same and dissimilar welds. The microstructure in dissimilar 6061-Al/2024-Al welds is significantly different from that in the welds of a 6061-Al alloy to itself. Vortex-like structures featured by the concentric flow lines for a weld of 6061-Al alloy to itself, and alternative lamellae with different alloy constituents for a weld of 6061-Al to 2024-Al alloy, are attributed to the stirring action of the threaded tool, in situ extrusion, and traverse motion along the welding direction. The mutual mixing in the dissimilar metal welds is intimate and far from complete. However, the bonding between the two Al-alloys is clearly complete. Three different regions in the nugget zone of dissimilar 6061-Al/2024-Al welds are classified by the mechanically mixed region (MMR) characterized by the relatively dispersed particles of different alloy constituents, the stirring-induced plastic flow region (SPFR) consisting of alternative vortex-like lamellae of the two Al-alloys, and the unmixed region (UMR) consisting of fine equiaxed grains of the 6061-Al alloy. Within all of these three regions, the material is able to withstand a very high degree of plastic deformation due to the presence of dynamic recovery or recrystallization of the microstructure. The degree of material mixing, the thickness of the deformed Al-alloy lamellae, and the material flow patterns depend on the related positions in the nugget zone and the processing parameters. Distinct fluctuations of hardness are found to correspond to the microstructural changes throughout the nugget zone of dissimilar welds.     

稀土钕对激光快速成形TC4合金组织及性能的影响

针对氢化脱氢钛合金粉末氧含量较高的问题，研究了添加稀土钕对激光快速成形TC4合金组织及性能的影响。结果发现，添加稀土Nd后，激光快速成形TC4合金的宏观晶粒尺寸变化不大；但随稀土添加量的增加，初始β列状晶逐渐转化为全β等轴晶，晶粒内部的魏氏α组织逐渐转变为网篮α，粗化α条不断增多，呈现团束聚集趋势，晶界α集束体积分数也不断增大；随稀土添加量的增加，激光快速成形TC4合金的室温塑性先大幅度提高，然后急剧降低；稀土添加量为0．1％～0．2％（质量分数，下同）时，氧含量为0．26％的氢化脱氢TC4合金粉末激光快速成形件沉积态的抗拉强度达975MPa，延伸率9．5％，满足锻件标准要求。