反应自生Al_3Ni－Al_2O_3－Al复合材料

通过热力学计算，选择Ｎｉ_２Ｏ_３粉末作原材料，采用反应挤压铸造方法实现了Ａｌ与Ｎｉ２Ｏ３直接压铸反应合成Ａｌ３Ｎｉ－Ａｌ２Ｏ３－Ａｌ原位复合材料。研究了压铸工艺参数和预制块中纯Ａｌ粉的含量对反应合成复合材料过程的影响，并对反应机理做了较深入的分析。结果表明，Ｎｉ２Ｏ３与Ａｌ的反应是为高放热反应，反应是爆发式的，通过调整预制块中Ａｌ粉的体积分数控制了反应的剧烈程度，并能获得不同组成和基体含量的复合材料。对反应机理的分析表明，在Ａｌ足量的情况下，Ｎｉ２Ｏ３与Ａｌ反应合成复合材料分为两个过程，一是反应过程，即Ｎｉ２Ｏ３＋Ａｌ→Ａｌ２Ｏ３＋［Ｎｉ］；二是凝固过程，即反应后多余的Ａｌ与反应生成的［Ｎｉ］在随后冷却中的凝固过程，最终形成Ａｌ３Ｎｉ＋α－Ａｌ２Ｏ３＋Ａｌ复合材料。     

TiO2—Al—B系反应烧结制备的复相陶瓷和原位Al基复合材料

采用反应烧结方法，利用ＴｉＯ２，Ａｌ和Ｂ粉末间的放热反应的较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合，Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ－０．８的多孔体，由尺寸小于２μｍ，在基体中呈现均匀分布，没有发现Ａｌ３Ｔｉ生成，这种原位Ａｌ基复合材料具有优于ＳｉＣｗ／Ａｌ复合材料的强度。     

TiO_2－Al－B系反应烧结制备的复相陶瓷和原位Al基复合材料

采用反应烧结方法，利用ＴｉＯ２，Ａｌ和Ｂ粉末间的放热反应在较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合材料Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ～０．８的多孔体，由尺寸约１０μｍ的生长单元构成晶粒，在陶瓷中还含有少量的Ａｌ３Ｔｉ．Ａｌ基复合材料中原位形成的Ａｌ２Ｏ３和ＴｉＢ２粒子尺寸小于２μｍ，在基体中呈现均匀分布，没有发现Ａｌ３Ｔｉ生成．这种原位Ａｌ基复合材料具有优于ＳｉＣｗ／Ａｌ复合材料的强度．     

TiO2／Al烧结反应生成的Al2O3／TixAly复合材料研究

采用挤压铸造法，先制备ＴｉＯ２／Ａｌ坯块，经随后高温烧结反应，可生成Ａｌ２Ｏ３／ＴｉｘＡｌｙ复合材料。ＤＴＡ分析表明ＴｉＯ２粉末与纯Ａｌ之间的反应具有放热特征。Ｘ射线衍射分析与透射电镜观察发现反应产物主要为α－Ａｌ２Ｏ３与ＴｉｘＡｌｙ。反应过程中ＴｉＯ２粉末首先被熔融态Ａｌ还原成α－Ａｌ２Ｏ３与Ｔｉ，而后Ｔｉ与Ａｌ通过扩散反应形成多种ＴｉｘＡｌｙ金属间化合物。     

AST液相添加剂对PTCR陶瓷电性能的影响

研究了液相添加剂ＡＳＴ（Ａｌ２Ｏ３＋ＳｉＯ２＋ＴｉＯ２）对ＢａＴｉＯ３陶瓷材料电性能的影响，随着Ａｌ２Ｏ３含量的增加，材料的电性能降低，ＳｉＯ２、ＴｉＯ２的物理特性对材料电性能影响较大，过量ＴｉＯ２对材料ＰＴＣ效应有重要影响。     

Al＋Ti＋C复合系热爆反应合成过程及相组成研究

研究了Ａｌ含量和Ｃ／Ｔｉ对Ａｌ＋Ｔｉ＋Ｃ复合系热爆反应合成Ａｌ／ＴｉＣ的反应过程及生成相组成的影响。实验结果表明：随着Ａｌ含量的增加，反应温度降低，反应时间延长，但反应起始温度几乎没有变化；Ｃ／Ｔｉ对反应温度和反应时间有很大的影响，但对反应起始温度影响很小。在对生成相组成的研究中发现：当Ｃ／Ｔｉ＝１．２５、Ａｌ含量不大于６０ａｔ％和Ｃ／Ｔｉ＝１、Ａｌ含量不大于５０ａｔ％时，生成物只有ＴｉＣ；随着Ａｌ含量的增加，生成Ａｌ＿３Ｔｉ的量增加，并通过热力学理论对反应合成自由能进行了计算，计算结果与试验结果相吻合。另外，通过扫描电子显微镜（ＳＥＭ）对生成的ＴｉＣ的组织形貌进行了观察。结果表明：生成的ＴｉＣ尺寸均匀，约为０．３～０．８μｍ，大多数呈球状，部分为块状。     

Al＋Ti＋C复合系热爆反应合成过程及相组成研究EI

研究了Ａｌ含量和Ｃ／Ｔｉ对Ａｌ＋Ｔｉ＋Ｃ复合系热爆反应合成Ａｌ／ＴｉＣ的反应过程及生成相组成的影响。实验结果表明：随着Ａｌ含量的增加，反应温度降低，反应时间延长，但反应起始温度几乎没有变化；Ｃ／Ｔｉ对反应温度和反应时间有很大的影响，但对反应起始温度影响很小。在对生成相组成的研究中发现：当Ｃ／Ｔｉ＝１．２５、Ａｌ含量不大于６０ａｔ％和Ｃ／Ｔｉ＝１、Ａｌ含量不大于５０ａｔ％时，生成物只有ＴｉＣ；随着Ａｌ含量的增加，生成Ａｌ＿３Ｔｉ的量增加，并通过热力学理论对反应合成自由能进行了计算，计算结果与试验结果相吻合。另外，通过扫描电子显微镜（ＳＥＭ）对生成的ＴｉＣ的组织形貌进行了观察。结果表明：生成的ＴｉＣ尺寸均匀，约为０．３～０．８μｍ，大多数呈球状，部分为块状。     

固体电子论分析CuZnAl记忆合金有序转变与马氏体稳定化

应用固体经验电子理论，计算了ＣｕＺｎＡｌ记忆合金中第４组元Ｎｉ和Ｍｎ对Ａ＿２→Ｂ＿２和Ｂ＿２→ＤＯ＿３两种有序转变温度的影响。计算得出：Ｎｉ提高而Ｍｎ降低合金的有序转变温度。这与Ｎｉ和Ｍｎ对合金的马氏体稳定化影响的趋势一致。表明固体电子论可以说明ＣｎＺｎＡｌ合金的稳定化和用来指导探索记忆性能好的合金。     

Al／SiC复合材料界面反应的DTA研究

本文以多层膜模拟复合材料界面反应，用ＤＴＡ及ＸＲＤ研究了ＴｉＣ，Ａｌ２Ｏ３和ＳｉＯ２作为Ａｌ／ＳｉＣ体系的反应阻挡层的作用．发现经７００℃，１ｈ处理后，Ａｌ２Ｏ３不与Ａｌ或ＳｉＣ反应，有很好的阻挡作用；ＴｉＣ与Ａｌ反应生成ＴｉＡｌ３后也能阻止Ａｌ与ＳｉＣ的反应；ＳｉＯ２与Ａｌ反应，导致一定数量的Ｓｉ溶入Ａｌ中，是否起阻挡作用有待进一步分析．     

TiB2颗粒增强NiAlFe基复合材料显微组织研究

研究了ＸＤ工艺原位生成ＮｉＡｌＦｅ－ＴｉＢ２复合材料的显微组织和界面结构,分析了Ｆｅ对材料压缩性能的影响及微观机制,加入２５％Ｆｅ元素后,形成的Ｆｅ（Ｎｉ,Ａｌ,Ｔｉ）新相以枝晶间的形式连接于基体之间以及基体与增强颗粒之间,提高了材料的塑性。运用高分辨电力显微术分析研究了压缩变形后增强颗粒与基体的界面。     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.