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中国有色金属学会会刊：英文版 2007年第4期17卷 669-675页

作者：熊翔盛洪超陈洁姚萍屏state key laboratory of powder metallurgy central south university state key laboratory of powder metallurgy Central South University

A novel Cu-based P/M aircraft brake material was prepared and the effects of sintering pressure and temperature on microstructure and tribological characteristic were investigated. For the constant sintering temperature, when the sintering pressure increases from 0.5 MPa to 1.5 MPa, the porosity, wear loss and friction coefficient decrease remarkably. When the sintering pressure increases from 1.5 MPa to 2.5 MPa, the porosity further decreases but in a little degree and wear behaviors are improved slightly. However, once the sintering pressure is larger than 2.5 MPa, it has no obvious effect on microstructure and tribological characteristic. For the constant sintering pressure, when the sintering temperature increases from 900 ℃ to 930 ℃, the sintered density remarkably increases, and wear behaviors are obviously improved. For further increasing sintering temperature to 1 000 ℃, the density keeps on increasing, but wear behaviors change slightly.

关键词：摩擦材料烧结压力烧结温度飞机制动材料铜基材料微观结构

Effects of Sc content on the mechanical properties of Al-Sc alloys

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Rare Metals 2010年第5期29卷 451-455页

作者： SUN Yingying,SONG Min,and HE Yuehui state key laboratory of powder metallurgy,central south university,Changsha 410083,China state key laboratory of powder metallurgy Central South University Changsha China

The effects of Sc content on the mechanical properties of Al-Sc alloys were investigated. The results show that the strengths of all the tested alloys with 0.1 wt.%, 0.3 wt.%, and 0.4 wt.% Sc additions increase initially with an increase in annealing time, due to the increase in volume fraction and size and the decrease in particle interspacing of Al3Sc particles. After reaching peak values, the strengths of all the tested alloys start to decrease with increasing annealing time due to the coarsening and increase in particle interspacing of At3Sc particles. It has also been shown that the alloy with 0.3 wt.% Sc has a higher strength and a lower elongation than the alloys with 0.1 wt.% and 0.4 wt.% Sc. The increase in strength and the decrease in elongation of the alloy with 0.3 wt.% Sc are due to the smaller particle interspacing of Al3Sc particles, resulting in a strong inhibition of dislocation movement during deformation.

关键词： aluminum alloys scandium mechanical properties microstructure

Development of Novel Binder for Hardmetal powder Extrusion Molding

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Journal of Materials Science & Technology 2002年第6期18卷 569-571页

作者： Jicheng ZHOU and Baiyun HUANGstate key laboratory for powder metallurgy, central south university , Changsha 410083, China Lab. for Power Metall. Central South Univ. Changsha 410083 China

A novel binder system for hardmetal powder extrusion moulding (PEM) process has been developed. The binder system comprises a major fraction of a mixture of low molecular weight components (LMWCs) and a minor fraction of very finely dispersed polymer. The feedstocks are mixed as a thick slurry at a suitable temperature and are rapidly homogenized by stirring at an adequate shear force. The binders are removed by thermal debinding. The thermal debinding mechanism has been investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). At the first stage of debinding, the LMWCs are removed. These open up pore channels which allows much faster removal of the remaining polymer component during the subsequent stage. The microstructures of the moulded green parts were observed by scanning electron microscopy (SEM). The debound samples were sintered at different temperatures, and the sintered samples properties were measured.

关键词： Binder Thermal debinding Hardmetal powder extrusion moulding

Direct Electrodeposition of Cu-Ni-W Alloys for the Liners for Shaped Charges

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Journal of Materials Science & Technology 2010年第5期26卷 429-432页

作者： Hanwei He and Shouya Jia state key Lab of powder metallurgy,central south university,Changsha 410083,China state key Lab of powder metallurgy Central South University Changsha 410083 China

The Cu-Ni-W alloys for the liners for shaped charges were successfully prepared by direct current（DC） *** influence of cathode current density on morphology,microstructure and composition of the Cu-Ni-W alloys was investigated by means of scanning electron microscopy（SEM）,X-ray diffraction（XRD） and energy dispersive spectrometry（EDS）.With the increasing of current density,the copper content reduces gradually and the nickel and tungsten content increase; the crystallite size is *** the current density is 15 A/dm 2 the tungsten content reaches 12.96 wt pct,and the crystallite size is submicron *** Cu-Ni-W alloy is face-centered cubic（fcc） solid *** of the Cu-Ni-W alloys take on（220） texture.

关键词： Electrodeposition Cu-Ni-W alloy Cathode current density

Thermodynamic analysis on synthesis process of diamond

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Journal of central south university 2001年第3期13卷 156-160页

作者： YI Jian-hong, PENG Yuan-dong (state key laboratory for powder metallurgy, central south university, Changsha 410083, China) state key laboratory for powder metallurgy Central South University Changsha China

Based upon the thermodynamic analysis of the nucleation of d iamond crystal, the effects of synthesis temperature and pressure on the nucleat ion of diamond crystal, diamond growth and output of diamond crystal, particle s ize and strength were discussed. The results show that the excess pressure has a n important effect on the critical radius of nucleation and thermodynamic b a rrier in the formation of a critical nucleus. Considering the excess pressure, t he expression of diamond nucleation rate was obtained.

关键词： diamond synthesis pressure temperature nucleation gr owth

A Novel Method for Preparation of TaC Coating on C/C Composite Material

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Journal of Materials Science & Technology 2005年第3期21卷 381-385页

作者： Hanwei HE, Kechao ZHOU and Xiang XIONG state key Lab of powder metallurgy, central south university, Changsha 410083, China Lab. of powder metallurgy Central South University Changsha 410083 China

A new method for preparation of TaC coating on C/C composite material is reported. The amorphous ethylate tantalum jellied as the precursor is prepared and spread densely on the surface of the C/C composite material so as to form a multilayer film. In a graphitization furnace the multilayer film is transformed into TaC coating at various temperatures. Ethylate tantalum film is characterized by FT-IR (Fourier transform infrared) spectra, XRD (X-ray diffraction) and SEM (scanning electron microscopy) and TaC coating is characterized by XRD and SEM. At 1200℃ the coating contained TaC and Ta2O5, and at above 1400℃ only TaC is formed. The coating formed at 1600℃ is a continuous stratum structure, and that formed at 1600℃ is a porous net structure. Analysis on thermodynamics and formation mechanism of TaC indicates that, after ethylate tantalum is decomposed, Ta2O5 is first produced and then transformed into Ta2C, and newly formed Ta2C is transformed into TaC by the sufficient C at last.

关键词： C/C composite TaC coating Ethylate tantalum

Growth of Hydroxyapatite Crystal in the Presence of Origanic Film

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Journal of Materials Science & Technology 2004年第2期20卷 223-226页

作者： Yong LIU, Suping HUANG, Xiaohong DAN and Kechao ZHOUstate key laboratory for powder metallurgy, central south university, Changsha 410083, China Lab. for powder Metall. Central South Univ. Changsha 410083 China

The growth of hydroxyapatite (HAp) crystal in the presence of hexadecylamine was investigated. Due to its high polarity and high charge density, the organic film could increase the ion supersaturation on its surface. Therefore the growth of pure HAp crystals was accelerated. Moreover, the positive headgroups of the organic film could act as recognized nucleation sites and orient the growth of HAp crystals along the 1> direction.

关键词： Biomineralization Hydroxyapatite Crystal growth

Synthesis of high grade octahedron diamond through epitaxial growth

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中国有色金属学会会刊：英文版 1999年第3期9卷 477-480页

作者： Yi Jianhong(易建宏) National key laboratory for powder metallurgy, central south university of Technology, Changsha 410083, P.R. China 中南工业大学粉末冶金国家重点实验室湖南长沙

The work was based on the relationship between the crystal structure and parameters of diamonds in the synthetic process, in which Ni Mn C powder catalyst was used. At first, the diamond crystals nucleated in a cubic octahedron morphology through controlling such synthetic parameters as temperature and pressure in a parameter region where cubic octahedron ctystals can be obtained. Then the diamond nuclei grew epitaxially into crystals with a perfect octahedron morphology through increasing the synthesis temperature and decreasing the synthesis pressure in a parameter region where octahedron crystals can be obtained.

关键词： high grade diamond eqitaxial growth

INJECTION MOLDED TUNGSTEN HEAVY ALLOY

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中国有色金属学会会刊：英文版 1998年第4期8卷 45-50页

作者： Li Yimin, Qu Xuanhui, Li Zhilin and Huang Baiyun state key laboratory for powder metallurgy, central south university of Technology, Changsha 410083, P. R. China state key laboratory for powder metallurgy Central South University of Technology Changsha 410083 China

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ＩＮＴＲＯＤＵＣＴＩＯＮＭｅｔａｌＩｎｊｅｃｔｉｏｎＭｏｌｄｉｎｇ（ＭＩＭ），ｗｈｉｃｈｉｓｄｅｒｉｖｅｄｆｒｏｍｐｌａｓｔｉｃｉｎｊｅｃｔｉｏｎｍｏｌｄｉｎｇ，ｉｓａｋｉｎｄｏｆｎｅｗｌｙｄｅｖｅｌｏｐｅｄｐｏｗｄｅｒｍｅｔａｌｕｒｇｙｆｏｒｍｉｎ...

关键词： injection molding heavy alloy powder loading

Properties Evolution of a powder Metallurgical Titanium Alloy with Yttrium Addition

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稀有金属材料与工程 2011年第S3期40卷 298-300页

作者： Liu Haiyan1, Tang Huiping1, He Weiwei1, Liu Yanbin2, Jia Wenpeng1, Liu Yong2 1state key laboratory for Porous Metals Materials, Northwest institute for Nonferrous Metal research, Xi′an 710016, China 2 state key laboratory for powder metallurgy, central south university, Changsha 410083, China NW Inst Nonferrous Met Res State Key Lab Porous Met Mat Xian 710016 Peoples R China Cent S Univ State Key Lab Powder Met Changsha 410083 Hunan Peoples R China

P/M Ti-Fe-Mo-Y alloys with different Rare-earth Y Content are prepared by blend element method, its sintering and hot deformation behaviors are studied together with microstructure and mechanical properties. The microstructures and properties of the alloying titanium were testified by the analysis of Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM).The result indicated that Y element absorbs free oxygen and purify the Ti powder surface, promoting densification process. With appropriate vacuum and temperature, the blend element metal powder sintering relative density can reach more than 97%. Microstructure and mechanical properties analysis shown that Y element composed Y2O3 particles which refine grains and improve plasticity, elevate alloy distortion ability. After hot deformation, grains crashed and flow line appears, the mechanical properties of Ti-Fe-Mo-Y alloy prompted which also validated by large amount of dimples appear in tensile fracture surface.

关键词： P/M Ti-Fe-Mo-Y alloy blend element method hot deformation