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Quick Search     Adv Search   2019 Vol. 29, No. 06 Published: 2019-12-10   1 The effects of W particle size on the structure and mechanical properties of tungsten-copper alloy strips prepared by warm powder rolling Hot! CUI Li-qun，HAN Sheng-li，LI Da-ren，HU Ke DOI: 10.13228/j.boyuan.issn1006-6543.20180062 Tungsten powder of different particle size thoroughly mixed with copper powder respectively, then the mixtures warm rolled into green strips at 100 °C .The green strips were sintered at 1350 °C to prepare tungsten-copper alloy strips. The effects of W particle size on the density and thickness of green strips were discussed. The structure and mechanical properties of the sintered alloy strips were investigated. The results show that the relative density of green strips increases and the thickness decreases with the increasing of W particle size. The larger the particle size of W powder, the smaller the relative density and the smaller the volume shrinkage of the raw slab after liquid phase sintering.But the larger W particle size, the more difficult W particle form sintering neck during liquid phase sintering, that is not conducive to generate W-skeleton and reduce the mechanical properties of tungsten-copper alloy strips. 2019 Vol. 29 (06): 1-5 [Abstract] ( 4 ) HTML (1 KB)  PDF (2161 KB)  ( 5 ) 6 Research on preparation of copper coated iron powder by mechanochemistry Hot! LI Shi-wen，PANG Jian-ming，FANG Jian-feng DOI: 10.13228/j.boyuan.issn1006-6543.20190125 A new preparation method of copper coated iron powder was proposed in this paper. Superfine copper oxide powder was coated on iron powder by mechanochemical effect and the Cu-coated Fe powder was obtained by hydrogen reduction and sintering. Under the action of mechanical force, oxidation-reduction reactions take place between Fe and CuO to produce Cu, Cu2O, Fe3O4, and the reacting types are consistent with the results from thermodynamic calculations. The superfine copper oxide powder after milling has higher surface defect density and surface energy, which provides better kinetic conditions for the reaction of Fe and CuO. During the process of H2 reduction, the product Cu nucleates and grows on the iron surface to get a good interfacial bonding. Meanwhile, sintering can dramatically bond copper particles, which densifies and homogenizes the copper coating layer． 2019 Vol. 29 (06): 6-12 [Abstract] ( 9 ) HTML (1 KB)  PDF (2355 KB)  ( 4 ) 13 Mechanical properties evolution of VC reinforced 316L stainless steel by selective laser melting Hot! LIU Zhi-yuan， QIAN Bo DOI: 10.13228/j.boyuan.issn1006-6543.20180055 The selective laser melting (SLM) technology based on 316L stainless steel powder has made good progress. The parameters of the SLM process have always been optimized for mechanical properties. In order to further strengthen the mechanical properties of 316L stainless steel forming parts, vanadium carbide (VC) ceramic particles with an average particle size of 800 nm were added to the original 316L stainless steel powder and the mechanical properties were tested after SLM forming. The results show that vanadium carbide is dissolved in the matrix, the hardness of the molded parts is raised about 22.8%, the yield strength is raised about 33.8%, the tensile strength is raised about 45.3%, and the modulus of elasticity is raised about 67%. Due to a slight increase in porosity, the elongation is reduced about 15.7%. 2019 Vol. 29 (06): 13-17 [Abstract] ( 14 ) HTML (1 KB)  PDF (2468 KB)  ( 5 ) 18 Study on ablation properties and mechanism of tungsten infiltrated copper composites Hot! ZHANG Bao-hong，ZHANG Dan-hua，GUO ying-li DOI: 10.13228/j.boyuan.issn1006-6543.20190080 Tungsten infiltrated copper composites, W-7Cu, were prepared by infiltration. The ablation properties of tungsten infiltrated copper materials were studied by pneumatic ablation test, and the ablation mechanism of tungsten infiltrated copper materials was analyzed. The results show that W-7Cu material has good ablation resistance. Under the condition of aerodynamic ablation test, the material is basically evenly ablated, and there is oxidation phenomena and copper precipitation on the surface. The ablation mechanism is oxidative ablation of tungsten and precipitative oxidation of copper. 2019 Vol. 29 (06): 18-22 [Abstract] ( 12 ) HTML (1 KB)  PDF (2436 KB)  ( 4 ) 23 Study on the wear resistance of Ni60-Cr3C2-WC/TiC plasma surfacing layer Hot! WANG Guang，WANG Hong-fu，ZHAO Wen，WANG Ze-yu，ZHANG yan DOI: 10.13228/j.boyuan.issn1006-6543.20180074 In this study, plasma surfacing technology was used to melt the mixed powders of Ni60, WC, Cr3C2 and TiC on the surface of the matrix in a certain proportion according to metallurgical bonding, and the performance of the teeth was improved by the excellent properties of the powder materials. The results show that the hardfacing layer is mainly composed of Ni-Cr-Fe austenite phase, boride hard phase and carbide hard phase. Because of the existence of these phases, the hardness of the surfacing layer is greatly improved. The microhardness of the third sample is 713.8HV, and the hardness is the highest among the three samples. The surfacing layer of the third sample wears completely at 180 min, and the total wear time is the longest. The wear resistance of the third sample is the strongest. 2019 Vol. 29 (06): 23-27 [Abstract] ( 9 ) HTML (1 KB)  PDF (1549 KB)  ( 8 ) 28 Powder metallurgy preparation and microstructure and properties of M2 high speed steel Hot! LUO Tao，JIANG Wen-qing，TONG Wei DOI: 10.13228/j.boyuan.issn1006-6543.20180134 M2 high speed steel powder was prepared by mechanical ball milling, studied the effect of sintering temperature on microstructure, hardness and bending strength of high speed steel, and the effect of heat treatment on microstructure and mechanical properties of high speed steel was analyzed. The results show that the particle distribution of HSS powder is uniform and the average size of HSS powder is the smallest when the milling time is 16 h, and there are no micro-holes or cracks in the samples; when the sintering temperature is 1 245℃, and the carbide is fine and dispersed. The sintering mechanism of HSS sample is solid phase sintering at 1 235 ℃,the relative density is 87.2%, and the sintering mechanism of HSS specimen is liquid phase sintering when the sintering temperature rises to 1 245 ℃ or above, and the relative density keeps above 98%. With the increase of sintering temperature, the wear weight loss of HSS specimen decreases first and then increases, and the bending strength increases first and then decreases. The hardness of the sintered samples can be further improved by quenching and tempering treatment. 2019 Vol. 29 (06): 28-33 [Abstract] ( 7 ) HTML (1 KB)  PDF (1917 KB)  ( 4 ) 34 Magnetic exchange coupling effect of nanocrystalline Sm-Co ribbons Hot! JIANG Zhi-yu， CHENG Hong-sheng, LIU Zhi-ying，ZHU Xiao-yu，FANG Yi-kun DOI: 10.13228/j.boyuan.issn1006-6543.20180066 In this paper, nanocrystalline Sm-Co ribbons were prepared by melt spinning method. The exchange coupling characteristics of Sm-Co ribbons were revealed by detecting the recovery curves of the ribbons. The effects of quenching speed and heat treatment on the exchange coupling effect of the Sm-Co ribbons were investigated. The exchange coupling effect was further confirmed by the characterization of magnetic microstructures by using magnetic force microscopy. It is found that with the increase of rapid quenching speed, the decrease of the average grain size increases the exchange coupling to a certain extent for the as-melt-spun Sm-Co ribbons. After heat treatment, the phase structure of the Sm-Co ribbons has changed, and the magnetic exchange coupling effect between the grains is enhanced. The irreversible magnetic field, Hn, of the as-melt-spun Sm-Co ribbons, 10 min- and 60min- heat treated ribbons is0.3 T，0.53 T，0.54 T respectively. The Hn of the SmCo ribbons without heat treatment is wider than the heat treated ribbons. The Hn distribution of the Sm-Co ribons after 60 min and 10 min heat treatment is basically the same. 2019 Vol. 29 (06): 34-40 [Abstract] ( 5 ) HTML (1 KB)  PDF (2248 KB)  ( 2 ) 41 10B areal density measurement and uniformity evaluation of Al-31%B4C composites Hot! CHEN Jin, XIONG Ning, GE Qi-lu, WANG Tie-jun, CAI Jing DOI: 10.13228/j.boyuan.issn1006-6543.20190114 The boron carbide enforced aluminum matrix composite was fabricated by hot isostatic pressing. The size of Al-31%B4C composite is 3 mm×200 mm×5000 mm. The density, tensile strength and microstructure of the composite were characterized. Measure the 10B areal density of Al-31%B4C by neutron transmittance measurements, calculate the 10B areal density of the Al-31%B4C flat which thickness is 3.05 mm, the result is 0.035 2-0.038 9 g ? cm-2. The data analysis of results show that the areal density of 10B is uniform throughout the Al-31% B4C flat, and the results meet the requirements of the neutron absorption engineering flats. 2019 Vol. 29 (06): 41-44 [Abstract] ( 8 ) HTML (1 KB)  PDF (1410 KB)  ( 4 ) 45 Microstructure and mechanical properties of W-Re-HfC alloy which fabricated by spark plasma sintering Hot! LIN Xiao-hui, LI Lai-ping, LIANG Jing, XUE Jian-rong, LI Yan-chao, ZHANG Xin DOI: 10.13228/j.boyuan.issn1006-6543.20190042 W-Re-HfC alloys with different HfC contents (1%, 5%, 10%, mass present) were fabricated by spark plasma sintering. The microstructure, room temperature compression properties and fracture toughness of W-Re-HfC alloys were observed and measured respectively. The results showed that with the increasing of HfC content, the relative density of sinter W-Re-HfC alloys decreased slightly, HfC particles are dispersively distributed within the grains and along with the grain boundary which refine the grain size apparently. The room temperature compression strength and fracture toughness of W-Re-HfC alloys were dramatically improved with increasing of HfC content, when the content of HfC from 1% up to 10%, the room temperature compression strength of alloy improved 80%. The W-Re-HfC alloys present a optimal compression deformability when the content of HfC was 5%. 2019 Vol. 29 (06): 45-50 [Abstract] ( 2 ) HTML (1 KB)  PDF (1935 KB)  ( 3 ) 51 Effect of cold deformation on microstructures and properties of Al2O3-dispersion strengthened copper for power cable Hot! ZHANG Jing-jie DOI: 10.13228/j.boyuan.issn1006-6543.20180070 The hardness, electrical conductivity, tensile properties and microstructures of Al2O3-dispersion strengthened copper alloy (Cu-5% Al2O3) for power cables with different deformation were tested. The results show that with the increase of deformation, the hardness of the alloy increases and the electrical conductivity does not change significantly. After cold rolling treatment, a remarkable work hardening phenomenon occurs. With the increase of deformation, the work hardening rate accelerates obviously. The growth rate of tensile strength and yield strength of the alloy is relatively stable, but the elongation decreases. After cold rolling, compact structure was formed in the alloy matrix, and no obvious holes or cracks were formed. Many fine grains with uniform size of about 300 nm with flat grain boundaries were formed in the alloy, resulting in high dislocation density in some regions. 2019 Vol. 29 (06): 51-54 [Abstract] ( 4 ) HTML (1 KB)  PDF (1273 KB)  ( 4 ) 55 Study on phenolic bonded TbDyFe magnetostrictive materials Hot! ZHAO Gui-Heng, LIU Yong-Qing, ZHANG Hong-Ping DOI: 10.13228/j.boyuan.issn1006-6543.20180057 The preparation and measurement of the magnetoelastic properties of bonded oriented alloy powder are reported. The experimental results show that the magnetostriction of material is significantly affected by the particle size and compaction pressure, samples with the particle size around 250~420 μm and the compaction pressure of 400 MPa has the largest magnetostriction 870×10-6 without prestressing. By 16-20 kHz magnetic field, the most remarkable factor of material loss is the compaction pressure, the material loss decreases to a lower level when the compaction pressure is higher than 400 MPa. 2019 Vol. 29 (06): 55-60 [Abstract] ( 2 ) HTML (1 KB)  PDF (2208 KB)  ( 4 ) 61 Study on the preparation and characteristics of (Bi2Te3)x/(PbSe)1-x Hot! ZHANG Yu-long,SHEN Yan ,Lü Zheng-ping ,XU Ye-jun，TANG Wen-chong DOI: 10.13228/j.boyuan.issn1006-6543.20180113 (Bi2Te3)x/(PbSe3)1-x are prepared by powder metallurgy method in this study. The compound powders of Bi2Te3 and PbSe are uniformly mixed and imposed by a cold-press pressure of 500 MPa, and then are sintered at 300 K for 1 hr. The microstructures and thermoelectric properties of these prepared test pieces are investigated. The studied results show that, many small particles are produced and a lot of Se pure phase is precipitated in these test pieces imposed by a great pressure, and their thermoelectric properties are seriously affected. The resistivity of the piece with x=0.4 is greater than that of other two pieces with x=0.5 and 0.6 and the resistivity of the piece with x=0.5 is the minimum at room temperature. The Seebeck coefficient of the piece with x=0.5 is the maximum (about 176.8 μV/K) at room temperature of and the Seebeck coefficient becomes greater with PbSe content increasing. The thermal conductivities of the two pieces with x=0.5 and 0.6 trend to constant for the measured temperature being more 280 K and the thermal conductivity of the piece with x=0.4 become smaller when the measured temperature is more than 230 K. The maximum value of thermal conductivity is about 1.772 W/(m·K) at room temperature for the test piece with x=0.5. The figure of merit (ZT) becomes greater with the measured temperature increasing and the maximum value of figure of merit is about 0.008 5 at room temperature for the test piece with x=0.5. 2019 Vol. 29 (06): 61-65 [Abstract] ( 3 ) HTML (1 KB)  PDF (1700 KB)  ( 4 ) 66 Synthesis and compaction behavior of copper matrix composite powders reinforced with ultrafine WC and nano-sized Al2O3 particles Hot! ZHANG Xiao-hong, SHEN Jing-yuan, Li Chao, HU Lian-xi DOI: 10.13228/j.boyuan.issn1006-6543.20190062 The process of mechanical milling for synthesis of Cu matrix composite powders reinforced with ultrafine WC and nano-sized Al2O3 particles was experimentally investigated. The evolution of the WC/Al2O3/Cu powder morphology, the distribution of the reinforcing WC and Al2O3 phases, and the grain size of the Cu matrix, due to mechanical milling, were characterized by XRD, SEM, and EDS analysis. The compaction behavior of the composite powders was characterized by room-temperature compaction tests. The results show that, by milling for 100 min with a rotation speed of 300 r/min and a ball to powder mass ratio of 10:1, Cu-based composite powders with uniformly distributed ultrafine WC and nano-sized Al2O3 reinforcing particles and an average size of about 0.4 μm for Cu crystallite grains can be obtained. In addition, the mechanically synthesized WC/Al2O3/Cu composite powders possess good compaction formability, and the compaction characteristics can be depicted by the well-known Huang’s double-logarithmic compaction equation. 2019 Vol. 29 (06): 66-70 [Abstract] ( 3 ) HTML (1 KB)  PDF (2165 KB)  ( 3 ) 71 A review on the methods and additive manufacturing application of spherical titanium alloy powder Hot! ZHAO Xiao-hao, WANG Chen, WANG Qi, PAN Fei-fei, WANG Qing-xiang, LAI Yun-jin, LIANG Shu-jin, ZHANG Ping-xiang DOI: 10.13228/j.boyuan.issn1006-6543.20180092 As the increasing applications of additive manufacturing(AM),Hot Isostatic Pressing(HIP), Cold Spraying(CS) and other powder metallurgy(PM), Spherical titanium alloy powder is one of the foundation for those near-net-shaping industries. Currently, there are four commercialized methods to manufacture spherical titanium alloy powder on a large scale, which are Supreme-Speed Plasma Rotating Electrode Process(SS-PREP), Gas Atomization(GA), Plasma Atomization(PA), Plasma Spheroidization(PS). The limitations and advantages among four methods were discussed and analyzed. Additionally, the cursory review of AM application with four kinds of powder was conduct. The result shows that there is no big difference in static mechanical properties. However, the measurable difference of dynamic mechanical properties occurs among four varying powders. Finally, the prospect of four methods was briefly developed and concluded. 2019 Vol. 29 (06): 71-76 [Abstract] ( 4 ) HTML (1 KB)  PDF (1863 KB)  ( 9 ) 77 Modification and application of nano titanium dioxide Hot! LI Yan，Yü Bo，ZHANG Xiao-qing，LIU Hui DOI: 10.13228/j.boyuan.issn1006-6543.20190132 Nanometer titanium dioxide (nano-TiO2) has the advantages of good chemical stability, non-toxicity, long service life, low production cost and is an ideal photocatalyst material. The common nano-TiO2 preparation methods are first introduced. Then the modification methods of nano-TiO2, including doping modification and surface modification are discussed. The photocatalytic activity of nano-TiO2 in visible light can be greatly improved after modification. Finally, the application field of nano-TiO2 is introduced, and the development prospect of nano-TiO2 is prospected. 2019 Vol. 29 (06): 77-81 [Abstract] ( 4 ) HTML (1 KB)  PDF (876 KB)  ( 7 ) 82 Preparation and characterization of diffusion alloy powder Hot! LI Rui，XU Jun，LI Hong-xia DOI: 10.13228/j.boyuan.issn1006-6543.20190083 In this paper, water atomized iron powder (FSY200.3) produced by Anshan Iron and Steel Powder Plant is used as raw material, ammonium molybdate, copper acetate and nickel acetate as coating agent, and the required metal is evenly diffused on the surface of water atomized iron powder by water immersion-hydrogen reduction method. The detailed process of preparing iron powder containing coated metal was investigated and the optimum technological conditions for the production of Fe-Mo-Ni-Cu alloy powder were determined. The reduced alloy powders were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The content of each element in alloy powder was determined by spectrophotometer. The bulk density, fluidity, compressibility and hydrogen loss of the reduced alloy powder were measured. The results show that all the technological parameters of the alloy powder prepared by water immersion and hydrogen reduction can meet the requirements. The hardness and tensile strength of the alloy powders (HJ) were measured by adding carbon powders with different mass fractions, and compared with those of the alloy powders (FSY-01K) prepared under the same conditions. The hardness and tensile strength of the alloy powders (HJ) prepared by the traditional method were higher than those of the alloy powders prepared by the traditional method. 2019 Vol. 29 (06): 82-85 [Abstract] ( 6 ) HTML (1 KB)  PDF (1231 KB)  ( 7 )

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