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International Journal of Minerals,Metallurgy and Materials 2013年第2期20卷 180-186页

作者： Hui Chen cheng-chang jia Shang-jie Li School of Materials Science and Engineering University of Science and Technology Beijing Shenzhen Haimingrun Industrial Co. Ltd.

Pure Cu composites reinforced with diamond particles were fabricated by a high pressure and high temperature （HPHT） infiltration technique. Their microstructural evolution and thermal conductivity were presented as a function of sintering parameters （temperature, pressure, and time）. The improvement in interfacial bonding strength and the maximum thermM conductivity of 750 W/（m.K） were achieved at the optimal sintering parameters of 1200℃, 6 GPa and 10 min. It is found that the thermal conductivity of the composites depends strongly on sintering pressure. When the sintering pressure is above 6 GPa, the diamond skeleton is detected, which greatly contributes to the excellent thermal conductivity.

关键词： metallic matrix composites particle reinforced composites copper diamonds infiltration microstructuralevolution thermal conductivity

Selective interfacial bonding and thermal conductivity of diamond/Cu-alloy composites prepared by HPHT technique

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 364-371页

作者： Hui Chen cheng-chang jia Shang-jie Li Xian jia Xia Yang School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Shenzhen Haimingrun Industrial Co. Ltd. Shenzhen 518126 China

Cu-based and Cu-alloy-based diamond composites were made by high-pressure-high-temperature （HPHT） sintering with the aim of maximizing the thermal conductivity of the composites. Improvements in interfacial bonding strength and thermo-physical properties of the composites were achieved using an atomized copper alloy with minor additions of Co, Cr, 13, and Ti. The thermal conductivity （TC） oh- mined exhibited as high as 688 W.m-1.K-1, but also as low as 325 W.m-1.K-l. A large variation in TC can be rationalized by the discrepancy of diamond-matrix interfacial bonding. It was found from fractography that preferential bonding between diamond and the Cu-alloy matrix occurred only on the diamond {100} faces. EDS analysis and Raman spectra suggested that selective interfacial bonding may be attributed to amorphous carbon increasing the wettability between diamond and the Cu-alloy matrix. Amorphous carbon was found to significantly affect the TC of the composite by interface modification.

关键词： metallic matrix composites diamonds copper alloys interfacial bonding thermal conductivity

Effect of sintering temperature on the microstructure and thermal conductivity of Al/diamond composites prepared by spark plasma sintering

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 234-240页

作者： Ke Chu cheng-chang jia Xue-bing Liang Hui Chen School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Spark plasma sintering was used to fabricate Al/diamond *** effect of sintering temperature on the microstructure and thermal conductivity（TC） of the composites was investigated with the combination of experimental results and theoretical *** composite sintered at 550℃shows high relative density and strong interfacial bonding,whereas the composites sintered at lower（520CC） and higher（580-600℃） temperatures indicate no interfacial bonding and poor interfacial bonding,*** relative density and strong interfacial bonding can maximize the thermal conductivity of Al/diamond composites,and taking both effects of particle shape and inhomogeneous interfacial thermal conductance into consideration can give a fairly good prediction of composites＇ thermal conduction properties.

关键词： metal matrix composites thermal properties spark plasma sintering interface

Spherical modification of tungsten oxide powder and its mechanism analysis

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Rare Metals 2015年第3期34卷 183-188页

作者： Cong-Cong Wang cheng-chang jia Peng Gao Guo-cheng Gai Yu-Fen Yang School of Materials Science and Engineering University of Science and Technology Beijing Powder Technology R&D Group Department of Material Science and EngineeringTsinghua University

Owing to its high production costs, complexity of equipment, and difficulty in controlling parameters, spherical or subglobose tungsten powder preparation method cannot meet the demand of industrial production. Tungstic oxide powder was treated by particle composite system and its effects were studied. Morphologies of par- ticles were investigated by scanning electron microscopy （SEM）. Particle size analysis was carried out and the related mechanism was discussed. The results show that the processing effect is best when the rotational speed is set at 4,000 ***-1 for 15 rain： the powder particles become nearly spherical and their sharp edge angles are rounded off and reshaped. When the processing time is 60 min, the powders smash to pieces because of too much energy inputting. So the test results, such as grain size distribution, can be explained well. Nearly spherical tungsten powder is obtained after reduction at 780 ℃ for 2 h and its flow ability is significantly improved.

关键词： Nearly spherical tungsten powder Grain size Modification Particle composite system

Fabrication and sintering behavior of high-nitrogen nickel-free stainless steels by metal injection molding

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International Journal of Minerals,Metallurgy and Materials 2010年第4期17卷 423-428页

作者： Zi-wei Xu cheng-chang jia Chun-jiang Kuang Xuan-hui Qu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Powder Metallurgy Division Advanced Technology ＆ Materials Co. Ltd. Beijing 100081 China

High-nitrogen nickel-free stainless steels were fabricated by the metal injection molding technique using high nitrogen alloying powders and a mixture of three polymers as *** of metal powders and binders with various proportions were also investigated, and an optimum powder loading capacity was determined as 64vol%.Intact injection molded compacts were successfully obtained by regulating the processing *** debinding process for molded compacts was optimized with a combination of thermo-gravimetric analysis and differential scanning calorimetry *** optimum relative density and nitrogen content of the specimens are obtained at 1360℃,which are 97.8%and 0.79wt%,respectively.

关键词： metal injection molding debinding stainless steel sintering behavior sintered density nitrogen content

Influence of plasma on the densification mechanism of SPS under multi-field effect

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International Journal of Minerals,Metallurgy and Materials 2014年第9期21卷 906-912页

作者： Yu-hong chang Di Huang cheng-chang jia Zhao-wen Cui Cong-cong Wang Dong Liang School of Materials Science and Engineering University of Science and Technology Beijing

The densification mechanism of an Fe-based alloy powder containing tiny oxide particles under the synergic multi-field effect of spark plasma sintering （SPS） was investigated. Metallographic microscopy and scanning electron microscopy were used to observe the morphology of samples sintered at different temperatures, and the temperature dislribution in an individual spherical powder particle during sintering was calculated in consideration of the influence of plasma, which was qualified and quantified through the analysis of the U-Icurve. The plasma was observed to play a substantial role in activating and heating the samples at the very early stage of sintering, whereas the joule-heat effect played a dominant role during sintering. Moreover, the plasma also facilitated the diffusion and migration of materials for neck formation.

关键词： iron alloys spark plasma sintering plasma temperature distribution densification diffusion

Microstructures and Mechanical Properties of X100 Pipeline Steel Strip

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Journal of Iron and Steel Research International 2014年第2期21卷 227-232页

作者： Lin-na DUAN Yu CHEN Qing-you LIU Shu-jun jia cheng-chang jia School of Material Science and Engineering University of Science and Technology Beijing Institute for Engineering Steel Central Iron and Steel Research Institute China Petroleum Engineering and Construction Corporation

Dynamic CCT （continuous cooling transformation） curves and effects of microstructures and M/A islands of X100 hot rolled strip on mechanical properties were studied by means of a thermal simulator, a scanning electron mi- croscope （SEM）, a transmission electron microscope （TEM）, a digital micro-hardness tester and Image-Pro Plus analysis software. The results show that high contents of C and Mo can make transformation lines of acicular ferrite and bain- ite shift rightward. High Mo tested strip has higher strength and micro-hardness and lower toughness than the other one because lath bainite appears instead of quasi-polygonal ferrite. Tested strip with granular bainite, lath bainite and M/A islands has better mechanical properties and in the microstructures lath bainite content is around 36.50% and M/A islands are fine and disperse in the matrix.

关键词： X100 hot rolled strip CCT curve granular bainite lath bainite M/A island

Effects of process parameters on nonaqueous gelcasting for copper powder

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International Journal of Minerals,Metallurgy and Materials 2016年第5期23卷 542-547页

作者： Karima Bekouche Zhao-li Wang cheng-chang jia Bo-wen Liu Yi Tang Institute of Advanced Materials and Technology University of Science and Technology Beijing

An approach to fabricate sintered copper with high green strength and high sintered density using nonaqueous gelcasting technol- ogy is presented in this study. The effects of various gelcasting processing parameters such as monomer content, monomer/crosslinker ratio, initiator content, dispersant dosage, and temperature on the flexural strength of dried green bodies and the relative density of sintered bodies were studied to obtain better microstructures and properties. The appropriate process parameters obtained for copper gelcasting are as follows monomer content, 20vol%-30vol% （based on the total volume of reagents）; monomer/crosslinker ratio, 10：1 to 20：1; initiator content, 3vol%-4vol% （based on the volume of the monomer）; dispersant dosage, 1.5wt%-2.5wt% （based on the mass of the copper powder）; and reaction temperature, 65-75℃.

关键词： copper powder gelcasting monomer process parameters flexural strength density

Low-temperature heat conduction characteristics of diamond/Cu composite by pressure infiltration method

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Rare Metals 2013年第6期32卷 579-585页

作者： Hong Guo Guang-Zhong Wang Xi-Min Zhang Fa-Zhang Yin cheng-chang jia School of Materials and Engineering University of Science & Technology Beijing

In this paper,diamond/CuCr and diamond/CuB composites were prepared using the pressure infiltration *** physical property measurement system(PPMS)was adopted to evaluate the thermal conductivity of diamond/Cu and MoCu composites within the range of100–350 K,and a scanning electron microscope(SEM)was utilized to analyze the microstructure and fracture appearance of the *** research indicates that the thermal conductivity of diamond/Cu composite within the range of100–350 K is 2.5–3.0 times that of the existing MoCu material,and the low-temperature thermal conductivity of diamond/Cu composite presents an exponential relationship with the *** B element was added to a Cu matrix and a low-temperature binder was used for prefabricated elements,favorable interfacial adhesion,relatively high interfacial thermal conductivity,and favorable low-temperature heat conduction characteristics would be apparent.

关键词： Diamond/Cu composite Low-temperature thermal conductivity Pressure infiltration

Aluminum matrix composites reinforced by molybdenum-coated carbon nanotubes

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International Journal of Minerals,Metallurgy and Materials 2011年第6期18卷 695-702页

作者： Jun-hui Nie cheng-chang jia Na Shi Ya-feng Zhang Yi Li Xianjia School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

To extend the application of carbon nanotubes （CNTs） and explore novel aluminum matrix composites,CNTs were coated by molybdenum layers using metal organic chemical vapor deposition,and then Mo-coated CNT （Mo-CNT）/Al composites were prepared by the combination processes of powder mixing and spark plasma *** influences of powder mixing and Mo-CNT content on the mechanical properties and electrical conductivity of the composites were *** results show that magnetic stirring is better than mechanical milling for mixing the Mo-CNTs and Al *** electrical conductivity of the composites decreases with increasing Mo-CNT *** the Mo-CNT content is 0.5wt%,the tensile strength and hardness of Mo-CNT/Al reach their maximum *** tensile strength of 0.5wt% Mo-CNT/Al increases by 29.9%,while the electrical conductivity only decreases by 7.1%,relative to sintered pure *** phase analysis of Mo-CNT/Al composites reveals that there is no formation of Al carbide in the composites.

关键词： carbon nanotubes aluminum matrix composites molybdenum layer mechanical properties electrical conductivity