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Quick Search     Adv Search   2020 Vol. 30, No. 04 Published: 2020-08-10   1 Application and feasibility study of additive manufacturing technology in automotive aftermarket Hot! PENG Jing-guang，ZHOUWei-xing，CHEN Di，DING Xia，WANG Xiang DOI: 10.13228/j.boyuan.issn1006-6543.20200090 The application status of additive manufacturing technology in the automotive aftermarket at home and abroad is summarized. It is pointed out that the application of additive manufacturing technology in the automotive aftermarket is mainly distributed in the two fields of aftermarket spare parts and personalized customization，and a feasibility study of the application is conducted. The main molding properties of common plastic materials and metal materials used in additive manufacturing technology and traditional manufacturing technology are compared. Taking specific plastic and metal parts as examples，the manufacturing costs of additive manufacturing technology and traditional manufacturing technology under different batches are compared. A market calculation model is established to estimate the potential market size of the additive manufacturing technology in the automotive aftermarket. Finally，the outlook for the application of additive manufacturing technology in the automotive aftermarket is made. 2020 Vol. 30 (04): 1-7 [Abstract] ( 3 ) HTML (1 KB)  PDF (1800 KB)  ( 4 ) 8 Study on material temperature increasing rule for preparing ultrafine iron powder by carbon thermal reduction in steel strip furnace Hot! GUO Pei-min，WANG Duo-gang，WANG Lei，KONG Ling-bing DOI: 10.13228/j.boyuan.issn1006-6543.20190137 In this paper，the heating temperature distribution of superfine iron powder and carbon powder mixture in steel strip furnace was studied by establishing the heating model of material in steel strip furnace. The main research results show that the material temperature is symmetrical distribution with the center of material thickness as the symmetrical point，the upper and bottom temperature is high，and the center temperature is low，when mixture of pure iron concentrate powder and carbon powder heating from the top and bottom of steel strip furnace. The thinner the material is，the higher the central temperature of the material is，and the shorter the heating time is. 50 mm material can be heated to 800 ℃ in 28 minutes，while 150 mm material can not reach 800 ℃ in 2 h. When the average temperature is heated to 800 ℃，the relationship between the time and the material thickness h is as follows： τ/min ＝13.24－0.021 h/mm ＋0.006 4h2. 2020 Vol. 30 (04): 8-11 [Abstract] ( 7 ) HTML (1 KB)  PDF (1350 KB)  ( 5 ) 12 Preparation of micro-nano Fe-Co-Cu prealloyed powder by mechanical-chemical alloying Hot! WANGWei，LI Cheng-wei，SUN Zhuo-nan，SONG Yi-tong，JIN Hui DOI: 10.13228/j.boyuan.issn1006-6543.20190094 In this paper，micro-nano Fe-Co-Cu prealloyed powder was prepared by mechanical-chemical alloying method. The effect of ball milling time，reduction time and temperature on the particle size and reduction rate of the reduced powder were investigated. The results show that the precursor powder has a narrow particle size distribution and uniform composition under the condition of ball milling time of 2 h and grinding aid content of 100 mL by mechanical- chemical alloying method. When the precursor is reduced at 650 ℃×60 min under hydrogen atmosphere，a micro-nano Fe-Co-Cu prealloyed powder with uniform particle size and low oxygen content can be obtained. 2020 Vol. 30 (04): 12-16 [Abstract] ( 3 ) HTML (1 KB)  PDF (1923 KB)  ( 4 ) 17 Study on properties of Fe-Mo-Ni-Cu-C powder metallurgy hydraulic motor valve plate Hot! ZUO Peng-jun， YANG Cong-bin，LIN Yu-yang，TONG Xiao-nan CHEN Xiao-xiao2，WANG Juan-mei1 DOI: 10.13228/j.boyuan.issn1006-6543.20190078 The Fe-Mo-Ni-Cu-C hydraulic motor valve plate samples were prepared by powder-metallurgy. The influence of C，Cu，Ni and other alloying elements in the valve plate on the material properties such as tensile strength，impact toughness，apparent hardness and radial size changes was studied. Fe-0.5Mo-0.6Ni-2Cu-0.7C is confirmed as the optimized valve plate material. The production practice and comprehensive performance test of the sintered valve plate parts prepared with this material are carried out，and the test results fully meet the requirements of the valve plate parts. It is verified that the Fe-0.5Mo-0.6Ni-2Cu-0.7C valve plate materials can be applied to the production practice and has reference significance for the research and development of similar iron-based powder metallurgy materials. 2020 Vol. 30 (04): 17-21 [Abstract] ( 3 ) HTML (1 KB)  PDF (1402 KB)  ( 6 ) 22 Effect of sintering process on mechanical properties of high precision stainless steel fiber felt Hot! HOU Li-qiang，GUO Liang，ZHUO Lei，LI Ming， ZHANG Xiao-qing，LUWen-jing DOI: 10.13228/j.boyuan.issn1006-6543.20190081 Sintering process was the core process of preparing fiber felt. Sintering temperature and holding time were two key points in the sintering process. The changes of surface morphology and sintering point size of 6 μm stainless steel fiber felt at different sintering temperature and holding time were observed by scanning electron microscopy. The effects of grain size and sintering point size of fibers on the mechanical properties of fiber felt were tested and a geometric model of sintering of ultrafine fibers was proposed. This provides data reference for the preparation of high precision stainless steel fiber felt. 2020 Vol. 30 (04): 22-25 [Abstract] ( 3 ) HTML (1 KB)  PDF (1479 KB)  ( 3 ) 26 Effect of Y2O3 on microstructure and mechanical properties of Ti-6Al-4V alloy connecting rod material Hot! WANG Kun-kun，LUO Tie-gang，DONG Ying-hu，ZHANG Rui-qing，FANG Jun-xiao DOI: 10.13228/j.boyuan.issn1006-6543.20190113 The effect of Y2O3 content on the microstructure and mechanical properties of Ti-6Al-4V alloy produced by spark plasma sintering（SPS）using the Ti-6Al-4V＋xY2O3（x＝0，0.2%，0.4%，0.6%，0.8%）powders as raw materials was investigated with optical microscopy and TEM. The results show that the grain size will be refined through adding Y2O3，when the content of Y2O3 exceeds 0.2%，the grain size will increase with the increase of Y2O3 content；and the mechanical properties of Ti-6Al-4V alloy can be effectively improved through adding Y2O3， when the content of Y2O3 equals to 0.2%，the Ti-6Al-4V alloy achieve its best mechanical properties，in which the yield strength，the maximum compressive strength and the compressive strain are 970 MPa，1 852 MPa and 31.4% respectively，and improves by 7.8%，14.1% and 19.4% respectively compared with Ti-6Al-4V alloy without adding Y2O3，and its densification increases to 99.28%. The Y2O3 mainly improves the mechanical properties of Ti-6Al-4V alloy by increasing the density of Ti-6Al-4V alloy and the pinning effect in the alloy. 2020 Vol. 30 (04): 26-31 [Abstract] ( 4 ) HTML (1 KB)  PDF (1825 KB)  ( 5 ) 32 Study on properties of graphite oriented copper-based friction materials Hot! SHI Yong-liang，ZHAO Xiao-ping，CHEN Cun-guang DOI: 10.13228/j.boyuan.issn1006-6543.20190167 Copper-based friction materials with oriented distribution of flake graphite were prepared by cold-pressing and hot-pressing sintering process with Al2O3 dispersion-strengthened copper powder as matrix and copper-plated flake graphite as lubricating phase. The distribution of flake graphite in copper matrix was observed by scanning electron microscopy，and the density，hardness，compressive strength，thermal conductivity and friction properties were tested and analyzed. The results show that the flake graphites are distributed uniformly in the copperbased friction material，and have good bonding between copper matrix. The graphite sheet tends to be perpendicular to pressing direction. The vertical compaction direction have higher hardness and compressive strength than the compaction direction. The thermal conductivity of the vertical compaction direction is three times higher than that of the compaction direction，and the friction coefficient，wear rate and friction surface temperature of the vertical compaction direction are lower than that of the compaction direction at high flake graphite volume fraction. 2020 Vol. 30 (04): 32-36 [Abstract] ( 4 ) HTML (1 KB)  PDF (1575 KB)  ( 8 ) 37 Effect of mixing time on properties of graphite-containing copper-based friction materials magnet Hot! LIU Jian-xiu，HAO Yuan-feng，FAN Jiang-lei，PAN Sheng-li DOI: 10.13228/j.boyuan.issn1006-6543.20190049 In this paper，copper-based friction materials were prepared by powder metallurgy method. The effect of mixing time on the properties of graphite-containing copper-based friction materials was studied by means of Brinell hardness tester，friction and wear tester and scanning electron microscope. The results show that with the increase of mixing time，the distribution of graphite in sintered friction materials becomes more uniform，the continuity of Cu matrix decreases， the density and hardness of materials decrease，the friction coefficient of materials increases first and then decreases， the wear loss decreases first and then increases. After addition of graphite，the sintered sample mixed for 8 h has the best friction and wear resistance properties.（Compared with other samples，the friction coefficient is increased by about 10%，the wear loss is reduced by about 30%） 2020 Vol. 30 (04): 37-41 [Abstract] ( 3 ) HTML (1 KB)  PDF (1607 KB)  ( 9 ) 42 Effect of deformation processes on the properties of Mo-Re foils Hot! CHEN Hai-feng，WANG Guang-da，XIONG Ning DOI: 10.13228/j.boyuan.issn1006-6543.20190139 For electronic application，Mo-Re alloy foils need have isotropy properties to warp or to deep draw. In this paper，we studied different deformation processes followed by heat treatments of Mo-35%Re alloy foils to get the preferred deformation processes to achieve isotropy. Through metallographic examination and mechanical property tests and cup tests，it is found that cross rolling improve the bend properties of Mo-Re foils，and different cross rolling processes can get different result. Further，it can be found that partial recrystallization annealing can get better mechanical properties and isotropy. So cross rolling process and followed partial recrystallization annealing can be used to improve the mechanical properties of alloys. 2020 Vol. 30 (04): 42-45 [Abstract] ( 3 ) HTML (1 KB)  PDF (1170 KB)  ( 3 ) 46 Magnetostriction and dynamic permeability of bonded Tb-Dy-Fe alloy powder magnesium alloys under high strain Hot! MU Xing，CHENG Chao，QI Yan，XU Li-hong，ZHAO Gui-heng，ZHANG Hong-ping DOI: 10.13228/j.boyuan.issn1006-6543.20200105 Phenolic resin was used to bond Tb0.27Dy0.73Fe1.95 alloy particles，and then the phenolic resin bonding composites were obtained by pressing and forming under the action of magnetic field orientation. The effects of powder particle size and forming pressure on its density，magnetostrictive properties and dynamic magnetic permeability had been analyzed. Samples prepared under 400 MPa forming pressure and with a powder size of 250-420 μm can reach a density of 6.6 g/cm3. The magnetostrictive coefficient under 400 kA/m magnetic field is 731×10－ 6， which is 110×10－ 6 higher than samples with a powder size of 38-58 μm. The permeability of the sample varies less than 2% in an ac magnetic field from 5 to 50 kHz，showing good frequency stability. Under the condition of alternating field superposition bias magnetic field，the permeability of the sample in the unbiased magnetic field at 1 kHz is 4.4，while at 1 528.3 A/m increases to 10.2，with an increase of over 131%. 2020 Vol. 30 (04): 46-50 [Abstract] ( 2 ) HTML (1 KB)  PDF (1490 KB)  ( 5 ) 51 Research on interfacial reaction of TiCp/Fe composites Hot! GENGWen-xia，WANG Qiu-lin，WAN Bin，XU Ru-tao，LI Ang，ZHAO Long-zhi DOI: 10.13228/j.boyuan.issn1006-6543.20190154 The interface reaction is easy to occur while the preparation of TiCp/Fe composites by powder metallurgy， which will affect its performance. In order to ascertain the sintering temperature and holding time of the interfacial reaction of the composite material，the microstructure and phase composition of the TiCp/Fe composite material were tested，and the thermodynamic process of the interface reaction was analyzed by thermodynamic principles. The results show that the critical temperature of the interface reaction between the reinforcement TiC and the matrix Fe is 1 270 ℃ by the thermodynamic calculation. When the holding time is 2 h and the sintering temperature exceeds 1 300 ℃，or the holding time is more than 2 h at 1 300 ℃，the interface reaction will occur between the reinforcement TiC and the matrix Fe in the experiment. The interfacial reaction generates some new needle-like substances（Ti8C5 and Fe2C），which affect the bonding strength of the reinforcement and the matrix，and reduce the performance of the composite. 2020 Vol. 30 (04): 51-56 [Abstract] ( 2 ) HTML (1 KB)  PDF (1987 KB)  ( 5 ) 57 Preparation of porous carbon nanosheets and its electrochemical performance Hot! XU Su-peng，ZHENG An-xiong DOI: 10.13228/j.boyuan.issn1006-6543.20190220 Two-dimensional（2D）porous carbon nanosheets were synthesized by a facile，low-cost method. Herein， coal tar pitch was used as a carbon precursor and sodium chloride was employed as a water soluble template. The highly porous carbon nanosheets were prepared by the carbonization of coal tar pitch and sodium chloride and the following KOH chemical activation. The as-prepared carbon nanosheets（AC-NaCl）possess a large specific surface area up to 1 581 m2/g. The resulting carbon sheets possess a thickness of less than 200 nm，which is beneficial to ion storage and transport due to the availability of more exposed active sites and the convenience of ion transport pathways. In 6 mol/L KOH electrolyte exhibits an outstanding capacitive performance（193 F/g ，1 A/g）， and a good cycling durability with over 94.9% capacitance retention after 5000 charge- discharge cycles at 1 A/g. 2020 Vol. 30 (04): 57-61 [Abstract] ( 2 ) HTML (1 KB)  PDF (1607 KB)  ( 4 ) 62 Effect of sintering temperature on the mechanics and friction properties of WNiCoFe alloy powder used for cutting tools Hot! JIANG Qing-gang，GE Xin-feng DOI: 10.13228/j.boyuan.issn1006-6543.20190156 In order to improve the wear resistance of WNiCoFe alloy for cutting tools，the powder of WNiCoFe alloy was prepared by electrolysis，and the influence of sintering temperature on its physical mechanics and friction properties was studied. The results show that in addition to Fe，diffraction peaks corresponding to Co3Fe7，Fe19Ni are also formed in the WNiCoFe alloy powder prepared by electrolysis. The powder of WNiCoFe alloy forms agglomerated grains with spherical characteristics，and the average particle size is 16.1 μm. With the increase of sintering temperature，the microstructure compactness and hardness of the alloy powder increases first and then decreases， and the maximum hardness of 108.6HRB is obtained at 800 ℃. The sample density reaches the maximum value of 95.4% at 850 ℃. With the increase of sintering temperature，the bending strength of alloy powder increases first and then decreases，and the maximum bending strength of 1 658 MPa is obtained at 800 ℃. With the increasing of the sintering temperature，the wear quality decreases，indicating that the wear resistance is improved. With the increase of sintering temperature to 800 ℃，the microstructure density of the sample is small，and many micropores are formed，which lead to the brittle fracture of intergranular. 2020 Vol. 30 (04): 62-66 [Abstract] ( 1 ) HTML (1 KB)  PDF (1681 KB)  ( 4 ) 67 Influence of nitriding process on properties of H13 hot work die steel Hot! TIAN Ze-ming DOI: 10.13228/j.boyuan.issn1006-6543.20190134 In this paper，the plasma nitriding process was carried out to treat the surface of H13 hot die steel. The experimental results show that the samples with the best property are achieved when the nitriding temperature is 500 ℃ and the holding time is 8 h，while the surface hardness is 1 250HV and nitriding layer thickness is 241 μm. The friction and wear test show that the wear loss quality of die steel samples with nitriding temperature of 500 ℃ and holding time of 8 h is 206 mg after 14 h of wearing test. The phase composition shows that the main compounds in nitriding layer are Fe2N，Fe4N and Fe3O4.The compound layer and nitriding layer with appropriate thickness have significant effect on the improvement of thermal properties of die steel. 2020 Vol. 30 (04): 67-70 [Abstract] ( 4 ) HTML (1 KB)  PDF (1255 KB)  ( 6 ) 71 Properties and microstructure of titanium-based powder coatings on aluminum alloys by laser cladding Hot! ZHANG Hong-yuan DOI: 10.13228/j.boyuan.issn1006-6543.20190218 Ti powder coating was prepared on the surface of Aluminium Alloy using laser cladding technology， the microstructure，the micro-hardness and friction and wear resistance properties of the laser cladding layer were tested. The results show that the microstructure of coating zone is dentrite，afterbirth- like crystal at transition zone，equiaxed grain at heat affect zone. The average hardness of the coating is 326.3HV，which is about 2 times higher than that of the substrate（120HV）. The wear resistance properties are significantly improved，and the mass loss is about 53 % of that the aluminum alloy，and coating surface is shallow plowing grooves. 2020 Vol. 30 (04): 71-75 [Abstract] ( 4 ) HTML (1 KB)  PDF (1494 KB)  ( 7 ) 76 Investigation of high-temperature mechanical property and fracture mechanism of tungsten alloy Hot! QIN Ying-nan，LIU Guo-hui，WANG Ling，LIU Gui-rong，XIONG Ning DOI: 10.13228/j.boyuan.issn1006-6543.20190061 In this paper，93W-5Ni-2Fe tungsten heavy alloy prepared by powder metallurgy method were tested at 1 000，1 100，1 200，1 300 and 1 400 ℃，the high temperature mechanical properties were investigated respectively. The fracture analysis and the developing principles of fracture mechanism were studied. The results show when the elevating temperature is 1 000- 1 400 ℃ ，mechanical properties of 93W- 5Ni- 2Fe alloy，such as tensile strength，elongation，reduction of area and Young's module get worsedramatically. Material becomes brittle，transgranular fracturecan be hardly found，binder phase tear and inter-facial fracture between tungsten grain and binder phases are domestic fracture mode. 2020 Vol. 30 (04): 76-78 [Abstract] ( 5 ) HTML (1 KB)  PDF (1387 KB)  ( 7 ) 79 Preparation progress in liquid phase method preparation for nanometer zirconia powder Hot! MAYang-yang，ZHANG Ning，XU Chen-hui，KAN Hong-min，WANG Xiao-yang，LONG Hai-bo DOI: 10.13228/j.boyuan.issn1006-6543.20190024 ZrO2 is an important new structural materials with stable chemical properties and special mechanical properties. This review summarizes the preparation process of nanometer ZrO2 Micro-Powder by Liquid，including precipitation method，sol-gel method and hydrothermal method，etc. The technological characteristics and main existing problems of preparing nanometer ZrO2 powder by Liquid phase method are introduced，and their application is also prospected. 2020 Vol. 30 (04): 79-82 [Abstract] ( 2 ) HTML (1 KB)  PDF (993 KB)  ( 4 ) 83 Progress on synthesis technology of nanodiamond particles Hot! ZHAOWan-lin DOI: 10.13228/j.boyuan.issn1006-6543.20190191 The nanodiamond particles，due to their superior properties such as superhardness，large specific surface area， high chemical inertness，facile surface functionalization and low toxicity，can be widely applied in many fields，including lapping，polishing，composites，nano lubrication，bio-medicine，quantum optics，quantum information and nano sensor，which have been attracting much attention throughout the world. In this paper，the synthesis methods of nanodiamond particles were mainly introduced and classified into dynamic and static synthesis according to their synthesis processes. 2020 Vol. 30 (04): 83-87 [Abstract] ( 2 ) HTML (1 KB)  PDF (1068 KB)  ( 3 ) 88 Application and analysis of countercurrent helix in mixture granulation molybdenum powder automatic screening platform Hot! GUO Hui-liang，XUE Cheng-da，QI Zhen-bao，HE Min，GU Lu-lu DOI: 10.13228/j.boyuan.issn1006-6543.20190048 This paper compares the granulation effect of adding counter-current helix in cylinder mixer. The results show that counter-current helix can increase the cumulative amount of medium and coarse particles from 70-75% to 80-85% on the screen of 3 mm after treatment，increase the proportion of spherical particles by about 15%， greatly reduce the proportion of rectangular and rod-shaped particles，increase the filling rate of mixer，and finally through rationalization. It is concluded that the theoretical curve of motion after adding countercurrent helix is helical reciprocating motion，which greatly increases the movement course and granulation time of granulating pellets compared with previous helical motion. 2020 Vol. 30 (04): 88-92 [Abstract] ( 2 ) HTML (1 KB)  PDF (1292 KB)  ( 3 )

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