块体纳米材料的制备技术与进展

块体纳米材料的制备技术是当前纳米材料领域内的一个热点.详细介绍了块体纳米材料的制备技术进展、应用及特点,对今后的研究及发展前景进行了展望.     

大塑性变形法制备块体纳米材料

综述了大塑性变形法制备块体纳米材料的发展、常用方法及其工作原理,介绍了大塑性变形法制备块体纳米材料应满足的基本条件,并在此基础上论述了大塑性变形法的实际应用,指出了目前大塑性变形法在制备块体纳米材料时存在的问题.     

三维块体纳米晶材料的制备及应用

综合评述了三维块体纳米晶材料的最新研究进展.概述了三维块体纳米晶材料的常用制备方法及新颖制备技术,并对各种制备方法进行了综合比较,指出其优缺点及已有实际应用的材料体系;介绍了三维块体纳米晶材料的性能表现;展望了三维块体纳米晶材料的未来研究发展方向及其在新领域的应用前景.     

块体纳米材料的制备及其应用

综述了块体纳米材料的制备技术及其发展,指出了常用方法存在的问题,并在此基础上论述了块体纳米材料的性能、应用及其发展趋势.     

纳米材料制备技术的研究现状

随着纳米科技的发展,纳米材料的制备显得非常重要.参阅了大量有关纳米材料制备技术的研究文献,对国内外纳米材料制备技术的研究现状进行了总结和展望,目前纳米材料制备技术一般按纳米颗粒、纳米线(管)、纳米薄膜、纳米块材等几方面进行发展改进.     

日本东邦钛业10年来首次亏损

纳米科技的科学意义体现在纳米尺度下的物质世界及其特性,是人类较为陌生的领域,也是一片新的研究疆土。纳米材料是指在三维空间中至少有一维处于纳米尺度范围或由它们作为基本单元构成的材料。在各种纳米材料研究中,纳米金属材料制备是当前研究的热点之一。然而,目前很多方法制备的纳米金属是“非理想纳米材料”,而要获得纳米金属的本征力学性能并研究其内在机理,从技术层面上要解决的瓶颈问题是必须制备出“理想纳米块体材料”——即全致密、无污染、晶粒尺寸均匀且完全驰豫状态的较大尺寸的纳米金属。     

纳米晶金属块体材料制备技术与力学性能研究进展

主要总结了纳米晶金属块体材料的制备技术与力学性能的研究进展.讨论了各种制备技术的特点与现存的问题,以及纳米晶金属块体材料的强度、塑性、应变速率敏感性、超塑性、变形机制与断裂机制等力学性能问题.     

生物分子法制备纳米材料研究进展

当前在国外纳米材料领域中兴起了一个热门课题--生物分子法制备纳米材料.综合介绍了近几年来生物分子法制备纳米粒子、纳米线、纳米管和纳米阵列等纳米材料的研究进展,提出了今后研究和改进的方向.     

多孔阳极氧化铝膜在纳米功能材料制备中的应用

纳米材料具有一系列不同于块体材料的新异特性，在许多领域都有着广阔应用前景。阳极氧化铝膜具有独特的多孔结构，可作为制备各种纳米功能材料的模板，因而在纳米功能材料制备中占有重要地位。本文综述了多孔阳极氧化铝模板的结构特征、制作方法及由模板合成法制备的多种纳米功能材料的研究与应用现状，并介绍了模板及纳米功能材料的常用表征手段。     

脉冲电沉积法制备纳米材料的研究进展

纳米材料具有特殊的磁性、光学、力学、电学、电化学催化等性能,而脉冲电沉积技术在制备纳米材料方面应用广泛且优点多.着重列举了脉冲电沉积技术在制备纳米晶材料、纳米复合材料、纳米析氢材料、纳米金属薄膜及纳米金属多层膜、纳米线材料等方面的应用,总结了纳米材料的一些特点,展望了脉冲电沉积技术制备纳米材料的前景.     

The Achievements of Advanced Manufacturing Techniques in Aviation and Aerospace Industries

In this paper, the recent achievements in the advanced manufacturing technology are presented. The laser forming of sheet metals, rapid forming, precision casting, precision forging, inertia friction welding are developed for aviation and aerospace industries. The main topics including the advantages, principle of manufacturing, processing parameters and control, typical processing applied in practice and typical work-pieces for those advanced manufacturing technologies are summarized.     

Verfügbarkeit von Metallrohstoffen für die Dünnschicht‐Photovoltaik

Availability of raw materials for the thin‐film photovoltaic on the example of gallium, indium and tellurium Gallium, tellurium, and indium are essential components used in the thinfilm technology which are predicted a growing demand. Their occurrence in the earth's crust is comparatively scarce thus they are produced and technically applied in small quantities. The trace metals are produced as a by‐product during extraction and refining of bulk metals such as aluminium, copper, or zinc. Essentially, the mining, processing and refining of the carrier element determines the maximum available production capacity. The global processing capacities of by‐products are limited, and the potentials of extraction are not fully utilized by current methods. Increasing the production of the by‐products would be achieved by increasing the production of the carrier elements or by extending the extraction capacities within an established production route. Moreover, the supply could be enhanced by processing currently untreated ores and concentrates as well as by treating residues from mining and processing.     

等离子合成与雾化制粉技术及其应用

等离子体做为一种极端参数技术在粉体材料的球化处理与合成制备方面的研究和应用日益引起人们的关注。本文概述了等离子技术的主要特点及应用领域,综述了国内外有关射频等离子体对不同金属粉末、陶瓷粉末的球化处理及纳米粉末的合成方面的研究成果;介绍了北京科技大学在射频等离子体粉体处理系统开发、制备球形钨粉和钛粉方面的研究成果,在此基础上对等离子体粉体球化处理技术的应用前景进行了展望。     

Ti-Al-Al2O3纳米粉体的机械活化-放电等离子烧结

TiAl基合金是很有发展潜力的高温结构材料,为实现快速高效制备此材料,采用新型的机械活化-放电等离子烧结(MA-SPS)制备纳米材料的有效方法,原位制备Ti-Al金属间化合物Ti-47%Al-10%Al2O3(Al为原子分数,Al2O3为质量分数)材料.介绍了放电等离子烧结这种新兴的纳米固体材料制备技术的特点,结合Ti-Al基合金的具体制备工艺,对MA-SPS的特征予以详细分析研究.通过X射线衍射、扫描电镜、透射电镜等分析,经机械球磨活化后,得到晶粒度小于24 nm的纳米单质元素粉体,为后续原位烧结提供合适的烧结原料.其中添加的Al2O3起到细化晶粒、促进纳米化和机械活化、提高出粉率等作用.纳米粉体在合适的参数下经放电等离子烧结后,可得到致密度达98.7%的(TiAl Ti3Al)理想双相组织,其成分的晶粒度小于91 nm,成为纳米固体材料.     

Near Net-Shaped, Alkaline-Earth-Bearing Ceramics for Electronic and Refractory Applications Via the Oxidation of Solid, Metal-Bearing Precursors (the VIMOX Process)

In most of the published work on the high-temperature oxidation of bulk metals, the resulting oxides are treated as undesired corrosion products. The opposite paradigm is discussed in this paper: bulk precursors containing alkaline earth metals (AE = Mg, Ca, Sr, Ba) are completely oxidized to produce electrical or refractory ceramics. Relatively dense AE-metal-bearing green bodies can be fabricated by either solid-state deformation processing or liquid metal infiltration processing. Rapid oxidation of the solid AE metals and reaction with other oxides in the green bodies can yield desired compounds. Unlike other oxides, AE oxides possess smaller molar volumes than the corresponding metals. Hence, by adjusting the amounts of AE and non-AE components in a precursor, an all-ceramic body with a shape and volume identical to the precursor can be produced (Volume Identical Metal Oxidation or VIMOX). The syntheses of shaped electronic titanates and cerates, and refractory aluminates and aluminosilicates, are discussed.     

The new trends in fabrication of bulk nanostructured materials by SPD processing

During the past decade, fabrication of bulk nanostructured metals and alloys using severe plastic deformation (SPD) has been evolving as a rapidly advancing direction of nanomaterials science and technology aimed at developing materials with new mechanical and functional properties for advanced applications. The principle of these developments is based on grain refinement down to the nanoscale level via various SPD techniques. This paper is focused on investigation and development of new SPD processing routes enabling fabrication of fully dense bulk nanostructured metals and alloys with a grain size of 40–50 nm and smaller, namely, SPD-consolidation of powders, including nanostructured ones, as well as SPD-induced nanocrystallization of amorphous alloys. We also consider microstructural features of SPD-processed materials that are responsible for enhancement of their properties.     

超微粉碎对苦荞物化性质的影响

目的实验探究超微粉碎对苦荞全粉物化性质的影响,为苦荞精深加工提供参考依据。方法以苦荞全粉为实验对象,研究剪切粉碎、气流粉碎和纳米研磨对苦荞基本化学成分、物理性质和抗氧化性的影响。结果通过测定不同方法处理所得苦荞全粉的流动性、含水量、持水力、蛋白质、黄酮等理化指标,发现粉体体积密度显著降低(P0.05),纳米粉体的流动性差异不显著(P0.05);脂肪含量和水分含量分别为5.00 g/kg和79.20 g/kg,下降趋势明显(P0.05)。纳米粉体的总酚含量与粗粉相比增加了19.46%,黄酮的含量增加了7.70%。经剪切粉碎和气流粉碎的粉体,其基本化学成分无较大变化。结论经纳米研磨所得苦荞粉具有较优的功能特性、营养品质,适合于苦荞的精深加工,是一种极具潜力的苦荞超微化方式。     

Severe plastic deformation processes for thin samples

Among the known severe plastic deformation (SPD) techniques, one particular group can be defined as SPD processing of thin samples. Their distinctive feature is that one of the sample dimensions, namely the thickness, is much smaller than the other two dimensions. Examples include High Pressure Torsion and two recently developed techniques: the Cone–Cone Method and the High Pressure Tube Twisting. The mentioned group of SPD processes involve frictional forces acting on the large surfaces and a high hydrostatic pressure within the deformation zone. These techniques are particularly suited for microforming of metals. In this article, we outline the commonalities between these three techniques. The microstructure of copper samples deformed by all the three processes is presented and compared with those obtained by equal-channel angular pressing as a reference bulk forming SPD technique.     

等离子体电弧法制备的带状纳米锌的表征

约束弧等离子体电弧法用等离子体高温热源激发高能粒子的化学反应,并与骤冷技术结合构成一个制备金属纳米粉体或化合物纳米粉末材料的等离子体过程,能极好地制备高溶点(例:Ni,Fe,C等)或低溶点(例:Al,Zn等)的纳米粉末,是当前极具工业化生产应用前景的方法之一。用约束弧等离子体电弧法制备了纳米Zn粉末,用XRD,TEM,TG,DTA技术研究了纳米Zn粉末的结构、晶粒大小、晶粒形貌和热稳定性。结果表明,该粉体平均粒径小于42 nm,晶粒形貌为带状,热稳定性好。此外该粉体具有高比表面积,可用作化学反应的催化剂。     

锻造技术在轻金属中的应用

随着社会的发展,材料的研发与设计向着轻量化、高强化发展,轻金属在航空航天以及汽车工业上表现出了良好的应用潜力,同时也对材料加工成形方式,如锻造技术等提出了更高的要求。简要介绍了金属锻造技术,如自由锻造、等温锻造和多向锻造技术,分析了锻造技术在轻量化金属如钛合金、铝合金以及镁合金上的应用,经过锻造处理后,金属的微观组织及力学性能得到了提升,锻件质量得到了改善。还介绍了数值模拟在锻造过程中模具设计及工艺优化上的研究及应用现状,同时对金属锻造未来向精密化、复杂化以及智能化的发展趋势进行了分析与展望。