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Synthesis of Ti_3SiC_2 by spark plasma sintering(SPS) of elemental powders

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中国有色金属学会会刊：英文版 2003年第1期13卷 46-49页

作者：朱教群梅炳初何利萍陈艳林 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Manufacturing Engineering and Engineering Management Faculty of Science and Engineering City University of Hong Kong Hong Kong

Ti 3SiC 2 materials have been fabricated by spark plasma sintering of the elemental powders with the addition of Al. At the heating rate of 80 ℃/min and under the pressure of 30 MPa, the ideal synthesis temperature of Ti 3SiC 2 is in the range of 1 1501 250 ℃. The addition of Al is in favor of the formation of Ti 3SiC 2. The synthesized compound has the molecular of Ti 3Si 0.8Al 0.2C 2 and lattice parameters of a=0.306 9 nm, c=1.767 0 nm. Its grain is plane-shape with a size of about 50 μm in the elongated dimension. The prepared material has Vickers hardness of 3.55.5 GPa(at 1 N and 15 s) and is as readily machinable as graphite’s.

关键词： Ti3SiC2 合成技术火花等离子体烧结粉末钛硅碳三元化合物

Influence of powder characteristics on structure and properties of Ni3Al fabricated by spark plasma sintering

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中国有色金属学会会刊：英文版 2006年第A02期16卷 112-116页

作者：孟杰贾成厂何箐 School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Three kinds of Ni and Al powder mixtures with nominal composition Ni75Al25 were employed to prepare Ni3Al alloys by spark plasma sintering(SPS) process. The raw powders include fine powder, coarse powder and mechanically-alloyed fine powder. The effects of powder characteristics and mechanical alloying on structure and properties of sintered body were investigated by scanning electron microscopy(SEM), X-ray diffraction(XRD), bending test and Vickers hardness measurements. For all mixture powders near fully dense Ni3Al alloys (relative density > 99.5%) are obtained after sintering at 1 150 degrees C for 5 min under 40 MPa. However a small fraction of Ni can be reserved for alloy from coarse powders. The results reveal that grain size is correlated with particle character of raw powder. Ni3Al alloy made from mechanically-alloyed fine powder has finer and more homogenous microstructure. The hardness of all alloys is similar varying from HV470 to 490. Ni3Al alloy made from mechanically-alloyed fine powder exhibites higher bending strength (1 070 MPa) than others.

关键词：粉末性质火花等离子体烧结 Ni3Al 机械合金化结构性能

SiC whisker reinforced MoSi_2 composite prepared by spark plasma sintering from COSHS-ed powder

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中国有色金属学会会刊：英文版 2006年第B02期16卷 504-507页

作者：许剑光张厚安江国健张宝林李文兰 Institute of Material Surface Engineering Hunan University of Science and Technology Xiangtan 411201 China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

SiC whisker reinforced MoSi2 composite powder was synthesized by a novel process, referred to the literature as chemical oven self-propagating high temperature synthesis(COSHS). The as-prepared SiCw/MoSi2 composite powder was rapidly sintered by spark plasma sintering(SPS) process. The sintering temperature and pressure were 1 723 K at heating rate of 100 K/min and 40 MPa, respectively. The microstructure and mechanical properties of the composite were investigated. Relative densities of the monolithic material and composite are 95% and 99.3%, respectively. SEM micrographs of SiCw/MoSi2 composite show that SiC whiskers homogeneously distribute in MoSi2 matrix. The composite containing SiC whisker has higher Vicker hardness than monolithic MoSi2. Especially the room-temperature fracture toughness of the composite is higher than that of MoSi2, from 3.6 MPa·m1/2 for MoSi2 to 7.7 MPa·m1/2 for composite with 15% SiC(volume fraction), increased by 113.9%. The morphology of propagation of crack and fractured surface of composite reveal the mechnaism to improve fracture toughness of MoSi2 matrix. The results show that the in-situ SiCw/MoSi2 composite powder prepared by COSHS technique can be successfully sinterded through SPS process and significant improvement of low temperature fracture toughness can be achieved.

关键词：碳化硅晶须 MoSi2 纤维增强复合材料火花等离子体烧结 COSHS技术粉末制备

Preparation and mechanism study of bulk pure rare-earth metals with amorphous and nanocrystalline structures

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Chinese Science Bulletin 2007年第3期52卷 418-422页

作者： LI ErDong SONG XiaoYan ZHANG JiuXing LU NianDuan College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials Ministry of Education BeijingUniversity of Technology Beijing 100022 China

The preparation and the mechanism study of bulk pure rare-earth metals with amorphous and nanocrystalline structures, which were produced by spark plasma sintering (SPS), were carried out in this paper. With different processing parameters, the amorphous, two phases of amorphous and nanocrystalline, and complete nanocrystalline microstructures have been obtained. The nano-grain sizes in the bulk nanocrystalline materials are found smaller than the original powder particles sizes, which may change the conventional viewpoint that the grains in the sintered bulk are generally coarser than the raw powder particles. The technique developed in the present work can be extended to the preparation of many other nano bulk metal materials, and thus enables the studies of the nano-size effects on the physical, chemical and mechanical properties of bulk nano materials.

关键词：块状稀土金属非晶态结构纳米晶结构火花等离子体烧结制备机制纳米材料

A bulk metal/ceramic composite material with a cellular structure

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Chinese Science Bulletin 2006年第2期51卷 235-239页

作者： ZHAO Zhankui YAO Kefu LI Jingfeng Key Laboratory for Advanced Manufacturing by Materials Processing Technology Department of Mechanical Engineering Tsinghua Uni versity Beijing 100084 China Department of Materials Science and Engineering Changchun University of Technology Changchun 130012 China State Key Laboratory of New Ceramic and Fine Process Tsinghua University Beijing 100084 China

A bulk metal/ceramic composite material with a honeycomb-like micro-cell structure has been prepared by sintering the spherical Al90Mn9Ce1 alloy powders clad by Al2O3 nano-powder with the spark plasma sintering (SPS) technique. The as-prepared material consists of Al90Mn9Ce1 alloy cell and closed Al2O3 ceramic cell wall. The diameter of the cells is about 20―40 μm, while a thickness of the cell wall is about 1―2 μm. The ultimate compressive strength of the as-sintered materials is about 514 MPa, while its fracture strain is up to about 0.65 %. This composite material might possess good anti-corrosion, thermal endurance and other potential properties due to its unique microstructure. The result shows that the Al90Mn9Ce1/Al2O3 composite powders can be sintered by spark plasma sintering technique despite the large difference in their sintering temperature. This work offers a way of designing and preparing metal/ceramic composite material with functional property.

关键词：金属/陶瓷复合材料多孔结构制备方法火花等离子体烧结

Mechanical alloying and characteristics of spark plasma sintering of Ti-Al composite powders

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中国有色金属学会会刊：英文版 2007年第A02期17卷 608-613页

作者：陈华薛涛门洪志 School of Materials Science and Engineering Changchun University of Technology

The mechanical alloying process of Ti-Al composite powders were carried out by use of high energy ball-milling machine. Structure variations of powder mixtures during mechanical alloying and characteristic of spark plasma sintering were investigated. The results show that during milling,TiAl,Ti3Al and Ti2Al phase intermetallic compounds are formed,simultaneously with powder refinement for the(TiH2-45Al-0.2Si-5Nb) and(TiH2-45Al-0.2Si-7Nb) mixtures. The particle sizes of two powder mixtures are less than 300 nm after milling for 30 h. Sintering process of the milled powder can be completed in a short time by spark plasma sintering,and the sintering microstructure is composed of fine and homogeneous TiAl and Ti3Al phase.

关键词：机械合金化钛铝金属间化合物火花等离子体烧结微观结构

Microstructure and properties of p-type (Bi_(0.25)Sb_(0.75))_2Te_3 fabricated by spark plasma sintering

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中国有色金属学会会刊：英文版 2007年第A02期17卷 1010-1013页

作者：王富强陈晖王忠成艳褚颖朱磊简旭宇 Energy Materials and Technology Research Institute General Research Institute for Nonferrous Metals

P-type thermoelectric material(Bi0.25Sb0.75)2Te3 was sintered by spark plasma sintering(SPS) process in the temperature range of 320-420 ℃. The microstructures of sintered materials were found to be well aligned,particularly when sintered at lower sintering temperatures. The electrical conductivity of the material became larger as the sintering temperature increased. The Seebeck coefficient showed a general decreasing tendency with an increase in sintering temperature. In terms of the power factor,the optimum sintering temperature was found to be 380 ℃ for a maximum value of around 2.6 mW/K.

关键词：热电材料火花等离子体烧结烧结温度微观结构性能