超细铜粉的制备及应用

介绍了采用化学合成法、新型电解法及高能球磨法制备超细铜粉的相关工艺,综述了超细铜粉在导电填料、复合材料及微电子材料等领域的应用.     

超细晶钨及其复合材料的研究现状

综述了自上而下和自下而上两种方法制备超细晶钨块体材料的研究现状.详尽概述了强塑性变形工艺、特殊烧结工艺制备超细晶钨的基本原理和特点.分析讨论了在强塑性变形加工及其粉末冶金法制备超细晶钨的影响因素及晶粒细化机制,指出了合理地采用弥散强化相,结合特殊烧结工艺和后期热变形加工工艺将是制备超细晶钨发展的主要方向.     

热处理对ARB制备超细晶1060工业纯铝组织和性能的影响

采用累积复合轧制(ARB)技术制备超细晶1060工业纯铝,研究了热处理对超细晶工业纯铝组织和性能的影响.结果显示,室温下1060工业纯铝经过ARB8道次轧制后,材料的晶粒尺寸由轧制前的38 μm细化至0.42μm,抗拉强度增加2.5倍,延伸率下降.ARB轧制后不同道次试样经150℃x 1 h热处理后,改善了材料层间界面的结合强度,使抗拉强度略有增加..ARB5道次轧制后试样在200℃以下热处理1 h,显微组织处于回复阶段,晶粒尺寸在0.478O.58μm范围内,机械性能稳定;在200℃以上热处理时,晶粒发生再结晶,晶粒长大,材料的性能恢复.     

HVOF喷涂超细WC-12Co耐磨涂层微观组织结构及性能研究

采用超细碳化钨和草酸钴为原料通过喷雾干燥造粒、氮气保护烧结、氢气还原等工艺得到WC-12Co超细热喷涂粉末材料.通过超音速火焰喷涂(HVOF)制备超细WC-12Co耐磨涂层.通过扫描电子显微镜对制备的WC-12Co超细热喷涂粉末材料及超细结构耐磨涂层的微观组织结构进行分析.对制备的超细结构耐磨涂层的结合强度、硬度进行表征.结果表明制备的WC-12Co超细热喷涂粉末材料适合于超音速火焰喷涂制备超细WC-12Co耐磨涂层,制备的超细WC-12Co耐磨涂层性能优异.     

超细和纳米钨粉制备技术进展

超细及纳米钨粉因优越的性能而具有广泛的应用前景,因此其制备技术一直是国内外研究热点。综述了超细和纳米钨粉的制备技术,着重介绍了氧化钨氢还原法、高能球磨法、溶胶凝胶法、冷冻干燥法制备超细及纳米钨粉原理和工艺的应用,并展望了超细和纳米钨粉制备技术的发展趋势。     

超细镍粉工艺现状与发展趋势

超细镍粉是一种重要的功能材料,具有广阔的应用前景,已成为我国功能材料开发的热点。文章介绍了国内外超细镍粉的制备工艺和方法,简要阐述各种方法研究现状及其优缺点,提出我国超细镍粉研究重点。     

超细钨粉的研究与应用

超细钨粉以其显著的特点成为多种重要功能材料和结构材料的重要原料,从而受到人们广泛的关注。目前,不少研究者通过实验探索出多种制备超细钨粉的生产工艺,由于这些方法对超细粉末的制备原理和工艺途径各不相同,由此所得到的粉末性能也存在差异。笔者介绍了超细钨粉的研究与应用现状及前景。     

超细/纳米硬质合金及晶粒长大抑制剂的研究

超细／纳米WC-Co硬质合金由于其优越的性能而获得更加广泛的应用,从而成为近年来各国政府研究学者及厂矿企业十分关注的热门话题。本文综述了国内外在超细／纳米硬质合金及晶粒长大抑制剂方面的研究进展。重点介绍了超细／纳米WC-Co复合粉末的制备技术和新的烧结工艺以及晶粒长大抑制剂的种类、添加方式和作用机理。     

机械合金化制备纳米级超细晶材料

机械合金化是一种很有发展前景的固态合金化方法 ,已成功地应用于制备纳米级超细晶弥散强化材料、磁性材料、超导材料、纳米晶材料等。介绍了机械合金化技术制备纳米级超细晶材料的发展及其工艺过程以及采用该技术制备的纳米级超细晶材料的力学性能、磁性能和储氢性能。     

超细WC-Co硬质合金研究综述

从超细WC-Co硬质合金的原料、晶粒长大抑制剂、制备工艺和过程机理等方面,综合评述了近年来国内外关于超细WC-Co硬质合金的研究成果。     

累积复合轧制工艺晶粒细化机制对1060工业纯铝组织和性能的影响

采用累积复合轧制(ARB)技术的两种工艺路径,研究变形后1060工业纯铝的显微组织和力学性能变化.结果显示:路径A的晶粒细化效果比路径B明显;ARB7道次后,采用路径A的试样的显微组织由拉长的细小纤维状晶粒组成,路径B的试样由扁平状晶粒组成;路径A和路径B的试样的平均晶粒尺寸分别为470nm和680nm;路径A的试样的抗拉强度提高程度大于路径B.1060工业纯铝在ARB过程中的强化机制主要是细晶强化.初步分析了ARB过程中材料的变形规律和细小晶粒的形成机制.     

Mechanical properties and bond strength of bimetallic AA1050/AA5083 laminates fabricated by warm-accumulative roll bonding

Accumulative roll bonding (ARB) is one of the most promising methods for the industrial production of bimetal sheet materials. In this study, ARB process has been used to combine aluminium alloys 1050 and 5083 sheets to produce a bimetal AA1050/AA5083 composite laminate. Materials with 2, 4, 8, 16 and 32 layers were roll bonded as alternate layers at 300°C for 5?min before each cycle. In this study, the microstructure and mechanical properties of composite laminates have been studied versus number of layers by tensile and peel testing. Moreover, the fracture surfaces of samples after the tensile test have been studied during various number of composite layers by scanning electron microscopy (SEM). Results showed that the tensile strength and tensile toughness improved by the number of layers. Also, the peeling strength among the layers and elongation decreased in the samples with less than 8 layers and improved by increasing the number of composite layers considerably. Also, SEM results revealed that the depth of dimples in the fracture surface decreased by increasing the number of layers.     

SOI材料的制备技术

SOI材料被誉为“二十一世纪硅集成电路技术”的基础。它可消除或减轻体硅中的体效应、寄生效应及小尺寸效应等 ,在超大规模集成电路、光电子等领域有广阔的应用前景。介绍了注氧隔离、智能剥离、硅片剥离及外延层转移等几种主要的制备SOI材料的方法及近期相关的研究成果。降低制造成本、提高材料质量以及获得足够薄的顶部硅层是近年来SOI材料制备技术改进的目标     

累积叠轧焊制备超细晶IF钢微观组织与力学性能

采用累积叠轧焊方法制备了超细晶IF钢，对其微观组织和力学性能进行了分析。实验结果表明，累积叠轧后IF钢的平均晶粒尺寸为700nm；抗拉强度为621．3MPa，达到冷轧IF钢抗拉强度的2．02倍，屈强比σ0.2/σb为0．81。在累积叠轧过程中产生的氧化物夹杂导致超细晶IF钢的脆化。     

累积叠轧焊强化金属材料的力学性能

在多功能热轧机上对广泛应用的代表性金属材料Q235碳素钢和L2铝分别进行了累积叠轧焊实验,重点研究了变形温度、累积叠轧次数和压下量对金属材料强度、应力-应变曲线、显微硬度、塑性的影响规律,分析了规律形成的原因.结果表明Q235碳素钢和L2铝在不加入任何强化元素的情况下完全可以达到良好的自身结合,材料的抗拉强度得到提高,金属材料的塑性分别有不同程度的下降.     

The use of organic compounds of phosphorus in clinical dentistry

Organic compounds of phosphorus have been developed for a range of applications in clinical dentistry. These include dentine bonding agents, restorative materials and therapeutic agents, such as active ingredients in anticaries mouthwashes. A characteristic feature of all of these applications is the good bonding of the phosphorus compound to the tooth. This review highlights the progress that has been made to date in preparing functional and durable organophosphorus bonding agents and cements, and includes coverage of recent synthetic work aimed at preparing improved organophosphorus molecules for this application. The review concludes that this remains a promising field of chemistry to explore in the search for improved, clinically useful dental materials.     

速凝法制备粘结稀土磁致伸缩材料的工艺和性能研究

采用甩带法制备了具有<112>织构的稀土磁致伸缩速凝片,以速凝片为基础,从粘结剂的种类和用量、样品的固化工艺等方面系统地研究了粘结稀土磁致伸缩材料的制备工艺,确定了较适宜的粘结剂用量为重量百分比4%,较好的固化工艺为150℃×2h.     

Microstructure and Mechanical Properties of AA5005/AA6061 Laminated Composite Processed by Accumulative Roll Bonding

The AA5005/AA6061 laminated composite has been fabricated by the accumulative roll bonding (ARB) using commercial AA5005 and AA6061. In the ARB process, one piece of AA5005 sheet and one piece of AA6061 sheet were stacked together and rolled with a 50 pct reduction without any lubrication. The materials were heated at 473 K (200 °C) for 10 minutes before each rolling process and were deformed up to four cycles to accumulate an equivalent strain of 3.2 and form an AA5005/AA6061 laminated composite. Mechanical properties and microstructure of the laminated composites were tested. The hardness and tensile strength increased, and the grain size reduced with the number of ARB cycles. Ultrafine grains elongated along the rolling direction were developed during the ARB process. The thicknesses of the grains of both the AA5005 and AA6061 layers were less than 200 nm after the fourth cycle. The uniform elongation decreased drastically after the first cycle ARB and stayed almost unchanged after further ARB process. The hardness of the AA5005 layer was slightly lower than that of the AA6061 layer. The microstructures from optical microscope and transmission microscope showed that in the AA6061 layer large precipitates in the micron scale and small particles less than 100 nm were present, whereas in the AA5005 layer there were large scale precipitates, but no small-sized particles.     

泡沫铝及其三明治结构累积叠轧制备

通过累积叠轧法制备泡沫铝.采用称重法研究泡沫铝孔隙结构,利用光学显微镜观察泡沫铝孔隙形貌.发现以TiH₂为发泡介质,当发泡温度660~680℃和发泡时间6~10 min时,利用累积叠轧法制备泡沫铝的孔隙结构特性最好.发泡温度和发泡时间的最佳值与发泡剂用量有关,TiH₂质量分数为1.5%,在670℃发泡8 min,泡沫铝的孔隙率可达到42%,孔径为0.43 mm.以制备的泡沫铝为夹芯,通过轧制复合制备了TC4钛合金/泡沫铝芯和1Cr18Ni9Ti不锈钢/泡沫铝芯三明治板.利用光学显微镜和能谱仪研究了三明治板的界面.面板与芯板间的化合反应形成了界面的反应层,界面实现了冶金结合.     

Microtexture Development of Niobium in a Multilayered Ti/Al/Nb Composite Produced by Accumulative Roll Bonding

Multilayered Ti/Al/Nb composites were produced by the accumulative roll bonding (ARB) process utilizing pure Ti, Al, and Nb element sheets. Up to four cycles of ARB were applied to the composites. The microstructure and texture evolution on the Nb phase were studied by X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscopy, and electron backscattered diffraction. Nb and Ti layers necked and fractured as the number of ARB passes increased. After four ARB cycles, a nearly homogeneous distribution of Nb and Ti layers in Al matrix was achieved. As-received Nb sheet exhibited a fully lamellar structure and had a strong cold-rolling texture. After subjecting to ARB, slight grain refining was observed and the high-angle boundary fraction was increased. The intensity of the α-fiber was weakened, while that of the γ-fiber was strengthened during ARB. The texture evolution was attributed to partial recrystallization during the ARB process as a result of adiabatic heating.