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Quick Search     Adv Search   2019 Vol. 29, No. 03 Published: 2019-06-10   1 Research progress of hybrid particles reinforced aluminum matrix composites Hot! GAO Hong-xia, WANG Meng, FAN Jiang-lei, WANG Yan, LI Ying, WU Shen DOI: 10.13228/j.boyuan.issn1006-6543.20180154 Hybrid particles reinforced aluminum matrix composite has the advantages of maintaining the advantages of all reinforcing phases, the synergistic hybrid effect of multiphase simultaneous enhancement, excellent comprehensive performance, etc., which has become a new research direction of composites at present. The research progress of hybrid particle reinforced aluminum matrix composites was reviewed in terms of hybrid types and main preparation methods. At the same time, corresponding solutions were put forward to the problems of uneven particle distribution, difficult determination of content ratio and interface effect in the current composite preparation process. Finally, the development prospect of hybrid particle reinforced aluminum matrix composite was prospected. 2019 Vol. 29 (03): 1-7 [Abstract] ( 5 ) HTML (1 KB)  PDF (1725 KB)  ( 3 ) 8 Effect of Si content on the microstructure and mechanical properties of W/W-10Cu diffusion bonded joint Hot! YAN Hai-xiang, FAN Jing-lian DOI: 10.13228/j.boyuan.issn1006-6543.20190023 Using Fe-Ni-Cu-Si as interlayer solder, W and W-10% Cu (W-10Cu) composite was fabricated through vacuum pressure diffusion bonding method. The effects of Si content in the interlayer solder on the microstructure and mechanical properties of the W/W-10Cu diffusion bonded joints was studied under the conditions of welding temperature of 1 050 ℃, holding time of 60 min and pressure of 20 MPa. The results show that the width of the diffusion layer gradually widens with the increase of Si content. When the mass percent of Si is 1.0%, a W-Ni-Fe diffusion layer with continuous composition distribution is formed at the interface. The hardness distribution shows a continuous and smooth trend, and the tensile strength reaches the maximum value of 296 MPa. 2019 Vol. 29 (03): 8-12 [Abstract] ( 6 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 13 Study on rolling process of titanium powder Hot! ZUO Bi-qiang,DING Wen-hong,HE Wen-jian,WU Gang DOI: 10.13228/j.boyuan.issn1006-6543.20170161 Titanium powder was rolled on a 4-high rolling mill, and the rolling process was analyzed by adjusting process parameters. The results show that the thickness of rolled products is directly proportional to roll diameter and feeding height. The greater the rolling speed, the smaller the thickness of the rolled strip; The smaller the roll gap, the smaller the thickness of the rolled strip, but the reduction value of the green strip thickness is smaller than that of the roll gap.get the velocity distribution and the mixing effect of the material during the working process. The influence of friction coefficient and rotation speed of the upper and lower swings on mixing effect of mixer was also analyzed. The results show that the speed of the particles close to the rotor blade is the highest and the speed of those close to the outer shell is the smallest. With the increase of the friction coefficient and the rotation speed of the upper and lower rotors, the better mixing effect is obtained, that is, increasing the rotation speed and the friction coefficient can improve the mixing effect of the mixer. 2019 Vol. 29 (03): 13-16 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 17 Study on properties of spherical silver powder for solar front silver paste Hot! ZHONG Xiang, HA Min, DONG Ning-li, ZHENG Wei, SHI Wen-feng DOI: 10.13228/j.boyuan.issn1006-6543.20180001 By means of scanning electron microscope, XRD, particle size distribution, specific surface area, tap density and other detection methods, the silver powder commonly used for solar front silver paste and other common spherical silver powder were analyzed and compared. The results show that spherical silver powder for solar front silver paste is a kind of polycrystalline silver powder with good sphericity, concentrated particle size distribution and tap density of 5.71 g/cm3. 2019 Vol. 29 (03): 17-22 [Abstract] ( 4 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 23 Effect of anodic oxidation forming process on electrical characteristics of niobium monoxide Hot! XU Ning-Hui, LIU Jun, WEI Chun-Xia DOI: 10.13228/j.boyuan.issn1006-6543.20170149 Niobium monoxide (NbO) has the similar electrical conductivity to metal. An oxide film with excellent dielectric property may be formed on the anode surface when oxidizzed as anode. Niobium monoxide sintered body was prepared by pressing and sintering of niobium monoxide powder. The effect of anodic oxidation process on electrical characteristics of niobium monoxide anodic oxidation film were studied. The results show that the optimum anodizing process of niobium monoxide sintered body anodic oxidation is: phosphoric acid solution conductivity of 2 000 μS/cm, forming solution temperature of 65 ℃, boosting current density of 100 mA/g, forming voltage of less than 50 V and constant voltage time of 180 min. 2019 Vol. 29 (03): 23-26 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 27 Study on influencing factors of reduction and melting of carbon-containing pellets Hot! LI Rong, GUO Jiang DOI: 10.13228/j.boyuan.issn1006-6543.20170155 The reduction and melting behavior of carbon-containing pellets was simulated by a high temperature resistance furnace. The effects of reduction temperature, reduction time, carbon/oxygen mole ratio and basicity of slag on the reduction and melting behavior of carbon-containing pellets were investigated. The results show that the lowest melting temperature for slag-iron separation is 1 360 ℃; The shortest reduction time is 18.0 min；The optimal carbon allocation (calculated by C/O) is 1.2; The binary basicity of slag should be controlled at 0.8-1.0. 2019 Vol. 29 (03): 27-31 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 32 Effect of reducing atmosphere on pressing properties of pure iron powder Hot! LIU Zhao-wa, YU Yong-liang, CHEN Kan DOI: 10.13228/j.boyuan.issn1006-6543.20180149 The reducing atmosphere is an important factor in reduction for removing impurities and oxides from iron powder to improve the chemical purity. It has an important effect on pressing properties. Through annealing reduction tests of LAP100.29 raw powder in the same production process and different reducing atmosphere, the influence of reducing atmosphere on the pressing performance of pure iron powder was studied. The results show that different reducing atmospheres have different effects on the pressing properties of iron powder, and the compression density of pure iron powder at 600 MPa reducing by hydrogen from ammonia decomposition is 0.02 g/cm3 lower than that reducing by hydrogen from methanol. Demoulding expansion rate and sintering expansion rate of pure iron powder by hydrogen from ammonia decomposition are also higher than those reducing by hydrogen from methanol. 2019 Vol. 29 (03): 32-34 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 35 Effect of Fe-Mo pre-alloyed powder on microstructure and properties of TiC steel-bonded cemented carbide Hot! LI Guo-ping,WU Ning,LUO Feng-hua,LIU Zeng-lin,YUAN Yong DOI: 10.13228/j.boyuan.issn1006-6543.20170167 TiC steel-bonded cemented carbide was prepared by conventional powder metallurgy process with Fe-Mo pre-alloyed powder and nickel, manganese, graphite additives as binder phase. The preparation process of the alloy was analyzed and optimized, and the effect of sintering temperature on the microstructure and properties of the alloy was studied. The results show that TiC particles become fine and round when Fe-Mo pre-alloyed powder is used as binder phase compared with pure Fe powder binder phase. With the increase of sintering temperature, TiC particles gradually grow up. Abnormal grain growth occurs when sintering temperature is 1 370 ℃. The alloy has the best comprehensive properties when sintered at 1 350 ℃. 2019 Vol. 29 (03): 35-40 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 41 Thermal friction and wear performance analysis of 30CrMnSiA copper-based powder metallurgy friction plate for clutch Hot! FU Chang-xing, ZHANG Xiao-xu DOI: 10.13228/j.boyuan.issn1006-6543.20180081 The MMU-10G friction and wear testing machine was used to test the friction and wear properties of the end face of 30CrMnSiA steel in the temperature range of room temperature to 600 ℃. The friction factor and wear amount were analyzed, with emphasis on the different wear mechanisms in light and heavy wear stages. At the temperature of 300 ℃, the friction plate is in the light wear stage. A smooth wear surface is formed. At the same time, some furrow structures with smaller depth are formed, and some crack structures are formed on the surface layer of large particles. The friction plate is mainly worn by abrasive grains, and at the same time there is a certain degree of oxidation wear. At the temperature of 500 ℃, the friction plate is in the heavy wear stage. More and deeper furrows are formed on the surface layer of the friction plate. Some SiO2 particles fall off and form pits. More Fe and Fe2O3 particles are formed in the abrasive dust. The wear mechanisms are oxidation wear, abrasive wear and fatigue wear. 2019 Vol. 29 (03): 41-45 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 46 Effect of Si content on microstructure and performance of W-Si composite prepared by plasma sintering Hot! ZHANG Fei-tian DOI: 10.13228/j.boyuan.issn1006-6543.20170124 The W/Si composites with different Si contents were prepared by mechanical ball milling and spark plasma sintering, and their microstructure and laser shock resistance were tested and analyzed. The results show that the powder distribution after ball milling treatment is more uniform and shows obvious refinement. With the increase of Si content, the degree of powder agglomeration gradually increases and reaches the maximum at 30% Si content. Si2W and W5Si3 phases are formed in the sintered sample. After sintering the W/Si composite powder, its density increases and its fracture mode is intergranular fracture type. When the mass percent of Si is 5%, the hardness of the composite is the highest, which is 1 146 HV. Three types of regions are formed on the surface of the composites after laser thermal shock, including melting region, affected region and unaffected region. The samples with higher damage degree are composites with 15%Si and 30%Si. 2019 Vol. 29 (03): 46-50 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 51 Preparation of Fe-based TiC-Al2O3 composite roller by vacuum pressureless infiltration Hot! QI Cui-fen,SHI Yong-liang,GUO Zhi-meng,CHEN Cun-guang DOI: 10.13228/j.boyuan.issn1006-6543.20170164 Ti-Al2O3 tubular porous skeleton with porosity as high as 75% was prepared by gel centrifugal forming process and vacuum sintering using sucrose as pore-forming agent. The prefabricated Fe alloy melt was vacuum pressureless impregnated at 1 400 ℃ for 30 min. Finally, a small composite roller with iron-based alloy core and Fe-TiC-Al2O3 surface was prepared. The microstructure and phase composition of the surface layer of the composite roller were tested and analyzed by scanning electron microscope and X-ray diffractometer, and the hardness, thermal shock resistance and wear resistance of the composite roller were measured. The results show that the core and surface layer of the prepared composite roller are well bonded without cracking. TiC is produced by reaction between Ti and C during infiltration. TiC is formed around Al2O3 particles to form an annular phase. The hardness of the surface layer reaches 65 HRC, and no obvious cracks appear after 10 thermal shocks at 800 ℃, while cracks appear in the surface layer near the bonding surface after 20 thermal shocks and spread along the bonding surface. In the wear test, Al2O3 particles are well bonded to the matrix without peeling off. 2019 Vol. 29 (03): 51-56 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 57 Effect of graphite and BN addition on wear performance of copper-based friction material for vehicle clutches Hot! DAI Shi-xun,ZHANG Zhu-lin DOI: 10.13228/j.boyuan.issn1006-6543.20180191 The wear performance of copper-based friction materials for vehicle clutches were studied when graphite and BN were used as lubrication components, and the effects of braking pressure, braking speed and temperature on the friction properties were analyzed. The results show that the wear rate of copper-based friction plate decreases with the increase of graphite content, and the friction coefficient increases with the increase of BN content. The best friction performance is achieved by adding 3% graphite and 2% BN (both mass percent). When the braking speed is 1 000 r/min, the friction factor and wear rate of the samples increase with the temperature rising. When graphite content increases and BN content decreases, the fluctuation range of friction coefficient of the sample also increases. After the friction test, more black massive graphite is formed in C1 sample, and the surface layer is also covered with graphite lubrication layer. BN film has obvious small block distribution characteristics. Its stability is lower than that of continuous large block graphite lubrication layer. BN film is easy to be destroyed and fall off during friction, causing matrix wear and a significant increase in wear rate. The comprehensive application of BN and graphite can achieve better lubricating effect than two single materials, thus obtaining good wear resistance at both room temperature and high temperature. 2019 Vol. 29 (03): 57-61 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 62 Application of scanning electron microscope and ball milling instrument in analysis of hard alloy coating Hot! LI Ying , JIANG Qi-jun DOI: 10.13228/j.boyuan.issn1006-6543.20170156 The combination of scanning electron microscope and ball milling instrument can effectively, accurately and comprehensively detect the performance of hard alloy NC blade coating. The results show that scanning electron microscope can be used to observe the morphology of the coating surface and cross section, energy spectrometer can be used to semi-quantify the coating composition, and ball milling instrument can be used to quickly and accurately detect the thickness of the coating and qualitatively analyze the bonding strength of the coating. The experimental results have a good guiding effect on the mechanism research, process research and quality control of hard alloy coating. 2019 Vol. 29 (03): 62-65 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 66 Research progress and prospect of microwave sintering technology Hot! XIE Meng-you, SHI Jian-jun, CHEN Guo-ping, LI Xiang DOI: 10.13228/j.boyuan.issn1006-6543.20180019 As a new sintering technology, microwave sintering has attracted increasing attention in the field of powder material forming and manufacturing. Compared with traditional sintering methods, microwave sintering has the advantages of high speed and efficiency, improvement of material microstructure, improvement of material comprehensive mechanical properties, energy conservation and environmental protection. The development process of microwave sintering technology was summarized. The manufacturing process and comprehensive properties of finished products of microwave sintering and traditional sintering were compared. The basic principle and research progress of microwave sintering were briefly introduced. The key influencing factors in microwave sintering technology were also analyzed. Finally, the existing problems of microwave sintering technology were summarized and analyzed, and the prospect was put forward, which provides necessary theoretical basis and reference for the further development of microwave sintering technology in China. 2019 Vol. 29 (03): 66-72 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 73 Research and development of a type of binder for premix powder Hot! SU Feng-ge, ZHENG Zhuo, WANG Zhi-rong DOI: 10.13228/j.boyuan.issn1006-6543.20170166 In order to reduce the segregation of mixed-powder and improve the powder quality, a new kind of binder for powder mixture was developed. 7 batches of Fe-2.0Cu-0.8C, 0.5MoFe-1.5Cu-1.8Ni-0.5C and 0.5MoFe-1.5Cu-3.8Ni-0.7C were prepared by adding different binder content (0-2.0%). Using scanning electron microscope (SEM) and optical microscope (OM) to observe the morphology of powder composition, distribution and phase composition of the sintered sample, the mechanical tester was used to measure the transverse rupture strength of the samples. Results show that adding binder effectively reduces the powder segregation, greatly reduces the dust in the process of blending and using, improves the consistency and loose density of samples. It also improves the fluidity and compressibility of the mixed-powder. The combined performance of powder is optimal when the binder content of 1.6%. The adhesion effect of the two kinds of mixed-powders prepared by using this binder are able to achieve the same level of imported mixed-powders. 2019 Vol. 29 (03): 73-77 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 78 The design of 850 tons ultra-large intelligent powder forming machine Hot! FENG Jin-yu DOI: 10.13228/j.boyuan.issn1006-6543.20180115 850 tons ultra-large intelligent powder forming machine is mainly composed of main body mechanical structure and transmission system, main control system and servo feeding system, which can realize the forming of complex structural parts with nominal pressure of 8 500 kN. The structural design process and technical characteristics of 850 t ultra-large intelligent powder forming machine were described from seven aspects including the main technical indexes and precision requirements, the structural design and analysis of key parts, the structural design of the main transmission part, the structural design of the upper sliding column part, the design of the servo feeding mechanism, the design of the intelligent system of forming process parameters and the design of the remote fault intelligent diagnosis expert system. The optimization design and analysis process of the whole machine structure of ultra-large intelligent powder forming machine were emphatically elaborated, and the automatic and intelligent control system was integrated into the design to improve the design capability and technical level of self-designed ultra-large powder forming equipment. 2019 Vol. 29 (03): 78-84 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 3 )

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