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Quick Search     Adv Search   2017 Vol. 27, No. 06 Published: 2017-12-10   1 Development status of metal injection molding in the world ZHANG Zhi-heng DOI: 10.13228/j.boyuan.issn1006-6543.20170130 Development status and application fields of metal injection molding （MIM） in recent years in north America， Europe， Japan， China and other Asian countries and regions were introduced. The high development speed and vigorous development trend of MIM as a new part manufacturing industry were described. It was also predicted that MIM industry has good development prospects with the progress of material and technology in MIM industry and the improvement of MIM products recognition. 2017 Vol. 27 (06): 1-7 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 8 Effect of different carbon and nitrogen sources on synthesis of （Ti，W）（C，N，B） solid solution powders ZHANG Zheng-quan，JIN Yong-zhong，YANG Lin，MING Yue-xing，JIANG Lun DOI: 10.13228/j.boyuan.issn1006-6543.20160090 （Ti，W）（C，N，B） powders were prepared from precursors by the carbothermal reduction method. Meanwhile， the effects of different carbon and nitrogen sources on phase composition and morphology of reaction products were investigated by XRD and SEM. The results show that nanocrystalline （Ti， W）（C， N， B） solid solution powders with single-phase structure are prepared at 1 200 ℃ when xylose and nitrogenare are used as carbon and nitrogen sources， respectively， and the operation process is simple and easy to control. When carbon black and phenolic resin with high molecular weight are used as carbon source， urea is used as nitrogen source， the carbothermal reduction and solid solution process are easily hindered， which result in a large number of intermediate phases of titanium oxide （such as Ti3O5， Ti2O3， etc.） and impurity phase （such as W） in reaction products. 2017 Vol. 27 (06): 8-12 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 13 Study on the optimum scale of nano vanadium nitride TIAN Jian，，ZHOU Yu，YE Bin，PAN Huang-yu，HUANG Zhi-lin DOI: 10.13228/j.boyuan.issn1006-6543.20160092 In order to study the advantages of nano vanadium nitride adding to steel， the characterization of the structure parameters of vanadium nitride was obtained through calculation of the crystal cell number， atom number and surface atom number. The optimum scale of nano vanadium nitride was calculated combined with the characteristics of nano particles. The results show that the optimum scale of nano vanadium nitride is 200 nm. The total atom numbers and the atom particles within the surface parallel to （001） get to a balance. 2017 Vol. 27 (06): 13-17 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 18 Preparation and application of Dy/Eu co-doped silicate phosphor by solid-phase reaction method ZHANG Hui-juan DOI: 10.13228/j.boyuan.issn1006-6543.20170049 The long afterglow phosphor Ca2MgSi2O7∶Eu， Dy was prepared by solid state reaction method， and then the phosphor was used as raw material for the preparation of fluorescent coating. The crystal form and luminescence properties of the materials were studied through X-ray diffraction， fluorescence spectrum and afterglow decay. The results show that the crystal structure of the phosphor is not changed with the addition of rare earth ions， and the phosphor has the strongest excitation and emission peak at 382 nm and 531 nm respectively， the afterglow time is as long as 15 h. With the increasing concentration of phosphor in fluorescent coating， the fluorescence intensity， viscosity and hardness of the coating are obviously enhanced， and the water absorption rate decreases significantly. The fluorescent coating prepared by Ca2MgSi2O7∶Eu， Dy material has the characteristics of long afterglow time and excellent weather resistance， which has a certain application potential in the field of fluorescent coatings. 2017 Vol. 27 (06): 18-21 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 22 Research on the size effect of PCL micro/nano fiber elastic properties under bending test YUAN Bo，QIU Yong-liang，HE Xian-yun，XU Yong-jun DOI: 10.13228/j.boyuan.issn1006-6543.20170087 A model based on non-local theory was built to anticipate the size effect of the elastic properties of PCL micro/nano fibers under three-point bending tests. The model forecast demonstrates that there are two sorts of size reliance for the bending tests， one is related with the fiber diameter， which is named as diameter size reliance （D-SD）， the other is related with the fiber length， which is named as length size reliance （L-SD）. The PCL micro/nano fibers were tested by atomic force microscope， and the calculation results of the three point bending experiment data and theoretical model of PCL micro/nano fibers were compared. It is demonstrated that the model can explain the scale effect of fiber elastic properties， and it also can be applied to the analysis of micro-elastic mechanical properties of other polymer fiber materials. 2017 Vol. 27 (06): 22-26 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 27 Finite element simulation of sintering process of 316L stainless steel powder injection molding KONG Xiang-ji，LIU Chao，KUANG Chun-jiang，GU Hu，WANG Fan DOI: 10.13228/j.boyuan.issn1006-6543.20170078 The micro metal injection molding （Micro MIM） technology has its unique advantages in the field of large-scale production of micro products. The feedstock based on fine 316L stainless steel powders was injected， debinded and sintered to manufacture tiny specimens. The constitutive behavior law of the feedstock based on fine 316L stainless steel powders was deduced， and the parameters such as shear viscosity， bulk viscosity and sintering stress were identified using Matlab? software. Finally， the shrinkage and relative density of 316L stainless steel powder during sintering were simulated by finite element method. The simulation results are in good agreement with the experimental data. 2017 Vol. 27 (06): 27-33 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 34 Study on mechanical properties of Monel porous plate GE Yuan，TAN Ping，LI Zeng-feng，WANG Jian-yong，WANG Qiang-bing，YANG Bao-jun DOI: 10.13228/j.boyuan.issn1006-6543.20170040 The porous plate is the key part for distributing gas in the fluidized bed， which is subjected to pressure， tension and shear from flowing gas and material during work. The porous plate is required to have excellent mechanical properties. The Monel porous plate was prepared by powder metallurgy process. The compression and shear properties of different parts were determined. Results show that the compression yield strength is up to 143 MPa and the elastic modulus reaches 18.1 GPa at the edge of porous plate. While in the central part of the plate， the compression yield strength is 67 MPa and the elastic modulus is 8.2 GPa. The elastic strain range is up to 3.0%. The shear strength is 153 MPa at edge and 87 MPa in the central. 2017 Vol. 27 (06): 34-38 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 39 Effect of Al（NO3）3 addition on the sintering properties and hydration resistance of dolomite ZHANG Wang-nian，DENG Ning DOI: 10.13228/j.boyuan.issn1006-6543.20160125 The MgO-CaO was prepared by the two-step calcination method through adding Al（NO3）3 in natural dolomite. The effects of Al（NO3）3 addition on the sintering properties and hydration resistance of dolomite were studied. Results show that， the MgO-CaO sample has the sintered density of 3.17 g/cm3， apparent porosity of 4.9%， hydration resistance weight gain rate of 3.1%， pulverization rate of 20.1%， and the MgO grain size of 2.92 μm when sintered at 1 600 ℃ for 3 h. The Al（NO3）3 decomposes into Al2O3， and Al2O3 reacts with CaO to form 3CaO2·Al2O3 at high temperature， thus the liquid phase forms during sintering， and promoting the sintering process of the samples. When adding 0.30% Al（NO3）3 （mass percent）， the MgO-CaO sample has the sintered density of 3.24 g/cm3， apparent porosity of 3.8%， hydration resistance weight gain rate of 2.0%， pulverization rate of 15.6%， and the MgO grain size of 3.48 μm when sintered at 1 600 ℃ for 3 h. 2017 Vol. 27 (06): 39-43 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 44 Research and application of high quality 3D printing metal powders for aerospace use HAN Shou-bo，，ZHANG Yi-wen，，TIAN Xiang-jun，LIU Ming-dong，，JIA Jian， DOI: 10.13228/j.boyuan.issn1006-6543.20170100 As the raw material for metal 3D printing， the properties of metal powers have a crucial impact on the quality of printing products. The precise and complex 3D printing parts used in the fields of aerospace， national defense and medical treatment have strict requirements for powder properties， such as particle size， morphology and purity. The basic requirements and main preparation process of high quality 3D printing metal powder applied to aerospace such as nickel base alloy， cobalt base alloy and titanium alloy and so on were introduced. The two commonly used preparation methods for high quality metal powders， i.e. vacuum induction melting argon gas atomization （VIGA） and plasma rotating electrode method （PREP）， were compared. It is pointed out that， the yield of fine powders prepared by VIGA is higher than PREP， but there exit hollow powders and satellite powders. By comparison， metal powders prepared by PREP are more suitable for preparing high quality 3D printing metal powders because of the advantages of high sphericity， smooth surface， narrow particle size distribution， good fluidity， low ceramic inclusion and so on. In order to improve the yield of fine powder and the efficiency of PREP method， it is suggested to develop a new generation of plasma rotating electrode atomizing technology and equipment. 2017 Vol. 27 (06): 44-51 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 52 Application status of SPS technology in powder metallurgy materials LIU Chun-rong，LIU Sheng-lin，ZHANG Wei-wei，DONG You-bang，YANG Jing-jing DOI: 10.13228/j.boyuan.issn1006-6543.20170107 As a new kind of powder solidification forming technology， spark plasma sintering technology has attracted extensive attention because of its high heating rate， short sintering time and high density of sintered materials. The application field of spark plasma sintering technology was summarized. The problems in the development process were analyzed， and the future development trend of spark plasma sintering technology was prospected. 2017 Vol. 27 (06): 52-56 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 57 Research progress in mechanical properties of sintered Nd-Fe-B magnets CHENG Xing-hua，，ZHOU Lei，LI Jian，LIU Tao，YU Xiao-jun，LI Bo DOI: 10.13228/j.boyuan.issn1006-6543.20160091 Sintered Nd-Fe-B magnets are brittle materials. Mechanical property is a very important index of the comprehensive performances of the magnets. The mechanical properties and processability of the magnet directly affect its service reliability and the cost of the manufacturing enterprise. The application fields of national defence and aviation have put forward high requirements for the shock resistance and overload performance of magnets. The mechanical characteristics of sintered Nd-Fe-B magnets were analyzed. The research results of improving mechanical properties were emphatically introduced， and the future development direction was prospected. 2017 Vol. 27 (06): 57-63 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 64 Research status and application prospect of high-entropy alloy LIU Qiu-lin，LIU Yun-zhong，WANG Yan-qun DOI: 10.13228/j.boyuan.issn1006-6543.20160115 The preparation methods， properties and application prospect of high-entropy alloys were summarized. High-entropy alloy is a new type of alloy developed in recent years， which usually contains more than five main elements， and the atom percent of each principal element is between 5% -35%. The microstructure and properties of high-entropy alloys are different from the traditional alloys in many aspects. With the deepening of the research on high entropy alloy， its application will be more and more wide， and the influence on all walks of life will be more and more. 2017 Vol. 27 (06): 64-69 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 70 Study on self-lubricating material used for pantograph of subway XIE Jian-quan， ZHANG Yan-lin DOI: 10.13228/j.boyuan.issn1006-6543.20170025 Cu-Sn-Ni-C self-lubricating liner was prepared by powder metallurgy technology. Results show that the sintered density is 6.70 g/cm3， the hardness is 375 HB， the crushing strength is 175 MPa and the oil content is 18.1% （mass percent） when the sintering temperature is 800 ℃ and the holding time is 80 min. The Cu-Sn-Ni-C self-lubricating liner was installed on the pantograph of the subway. After the operation of 50 000 km， the inner hole of the self-lubricating liner has no fracture and abnormal phenomenon except for a small amount of wear， which fully meets the requirements of the metro pantograph. 2017 Vol. 27 (06): 70-74 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 2 )

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