15 April 2014, Volume 45 Issue 07
    

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    研究 开发
  • . 2014, 45(07): 1-0.
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    Abstract: Three-phase composite electrode composed of graphene, manganese dioxide, and poly(3,4-ethylenedioxythiophene) is obtained by potentiostatic method. The manganese dioxide and poly(3,4-ethylenedioxythiophene) layers are prepared on the surface of graphene, with aqueous solution as electrode. The morphology characteristics and the composite structure of the three-phase composite electrode are characterized with scanning electron microscope (SEM). The electrochemical properties of composite electrode are measured by constant current charge-discharge, cyclic voltammetry, and alternating current impendence (AC impedance) methods. The results show that the grapheme is special fold structure, the manganese dioxide is irregular nanosheets, the poly(3,4-ethylenedioxythiophene) is aggregated by nanoparticles, the three-phase composite electrode is layered composite structure. The specific volume is 165F/g under 1.0A/g charge-discharge current. The capacity maintains 80% after 500 charge-discharge cycles which show good stability. The three-phase composite electrode presents very good discharge reversibility and impedance–resistant.
  • Shi-Zhou YANG;
    . 2014, 45(07): 2-0.
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    To further improve shape memory effect in a Fe13Mn6Si13Cr4Ni0.1C alloy, the effect of different amount of pre-deformation on microstructure and shape memory effect in alloys aged at 1073 K was studied. The results showed that the shape recovery ration in alloys aged after 10% pre-deformation can reach (86.1±1.0)% at 300 min, increased by 169% compared to 32% in a water-quenching alloy. And the shape recovery ration in aged alloys following 5% pre-deformation rises up to the maximum value (82.9±1.0)%at 180 min, increase by 159% compared with 32%, but it slightly decreases with ageing time over 180 min. The shape recovery ration for directly aged alloys without pre-deformation reaches the peak value (46.3±1.0)% at 180 min, higher 44.7% than 32%, but it gradually falls down over 180 min. By SEM and XRD analysis it was found that aligned Cr23C6 particles precipitated from alloys aged after 10% pre-deformation are the most, the smallest among the above three alloys. It was just the reason that makes more improvement in shape memory ration for aged alloys following 10% pre-deformation than that for alloys aged after 5% pre-deformation and directly aged alloys.
  • ;;;Jun-Xia ZHUANG
    . 2014, 45(07): 3-0.
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    The electrodes of polyaniline and polyaniline doped with Mn2+ (PANI/Mn2+) were prepared via interfacial polymerization method. The structure and morphology of PANI and PANI/Mn2+ films were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The electrochemical properties of PANI and PANI/Mn2+ films were investigated by cyclic voltammetry, galvanostatic charge-discharge test and electrochemical impedance spectroscopy (EIS) in 0.5 mol/L H2SO4 electrolyte in three-electrode system. The results suggest that the growth rate of PANI was greatly increased, which may arise from the interactions between PANI chains and Mn2+. The PANI/Mn2+ films show a larger specific capacitance of 403 F/g at a current density of 5 mA/cm2 and lower resistance compared with the pure PANI film. The results indicate that the PANI/Mn2+ films are promising material for supercapacitors.
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    . 2014, 45(07): 4-0.
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    Abstract: In this paper, the rules of conductivity of BaCo0.7Fe0.2Nb0.1O3-δ (BCFN) ionic-electric mixed conductor changing with temperature is studied by the four-probe method; the ionic conductivity of BCFN changing with temperature is obtained by the electrode-blocking method and then calculated the electric conductivity. As our results revealed, the electric carriers play an dominant effect in the conductor and electronic transport number is near 100% when the temperature is below 550℃. The whole conductivity and electric conductivity increase rapidly with the evaluating temperature, which exhibits a characteristic of P-type semi-conductor with the apparent electric activation energy of 0.30ev. When the temperature is at the range of 550~650℃, the electric conductivity decreases because of electric carrier consumption resulting from the lattice oxygen desorption. Since the oxygen vacancy increases when the temperature is above 650℃, the ionic conductivity and oxide-ionic transport number increase rapidly with rising temperature and enhance the whole conductivity as well. The oxide-ionic transport number is up to 8.97% at 900℃.The calculated migration activation energy of oxygen vacancy here is 1.18eV. Moreover, the desorption peak observed in the O2-TPD experiment at the range of 550~650℃ provides a powerful proof of the lattice oxygen desorption, which make a remarkable effect on the ionic conductivity and whole conductivity of BCFN.
  • Yan-Wei TONGGao Jiao Cheng
    . 2014, 45(07): 5-0.
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    To obtain V-based hydrogen storage alloys with high discharge capacity and good cycle stability, the V1.95Ti0.5Cr0.5NiO0.05AlxFey (x, y =0~0.05) hydrogen storage alloys were prepared by induction melting, and the effect of Al and Fe contents on the microstructures and electrochemical property was investigated systematically. X-ray diffraction (XRD) indicates that all of the alloys mainly consist of a V-based solid solution phase with a BCC structure and a TiNi-based secondary phase. The electrochemical measurements show that the addition of Al improves the maximum discharge capacity and high rate discharge ability while the increase of the Fe content improves the cycle stability.
  • Lian ZHANG;;;;Shen LIN
    . 2014, 45(07): 6-0.
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    Abstract: Graphene (GN) was functionalized by the water-soluble polymer polyethyleneimine (PEI) to enhance its solubility and dispersity. The {PEI-GN/PW12}n composite films composed of functionalized graphene (PEI-GN) and phosphotungstic acid (H3PW12O40, PW12 for short) were prepared by LBL electrostatic assembly technique, and then it was used as a substrate for electro-deposition Pt nanoparticles cluster in-situ by cyclic voltammetry. The fabricated composite films were characterized by ultraviolet-visible spectrophotometry (UV-vis), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). Cyclic voltammetry (CV), chronoamperometry (It), CO stripping voltammetry and electrochemical impedance spectra (EIS) analysis show that the Pt/{PEI-GN/PW12}n has superior eletro-catalytic activity, stability and ability to resist CO poisoning regarding methanol oxidation.
  • Zhen FU; ;
    . 2014, 45(07): 7-0.
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    Li-rich layered cathode material, LiNi0.5Mn0.5O2 and Li1.2Ni0.3Mn0.5O2 were synthesized via a solution method. The structure and morphology of the prepared materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM). Galvanostatic charge/discharge studies demonstrated the electrochemical performance of two materials. It was found that the material LiNi0.5Mn0.5O2 delivers initial discharge capacity of 125. 6mAh/g and retains a reversible capacity of 111. 2mAh/g after 30 cycles with a capacity retention of 96. 2%. While the sample Li1.2Ni0.3Mn0.5O2 exhibited not only a higher discharge capacity of 187. 2mAh/g, but also excellent cycling performance with a capacity retention of over 98. 6% after 30 cycles. In addition, the Li-rich Li1.2Ni0.3Mn0.5O2 shows better rate capability.
  • Hai-Quan FENG ;
    . 2014, 45(07): 8-0.
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    Using finite element method (fem) of 6 kinds of magnesium alloy with different structure of coronary artery stent for simulation analysis. The purpose of this paper is to study and compare flexibility of different stents. Results show that, in the profiling state, different connection bars of stents have bigger effect on their flexibility. The flexibility of S-stent is better,instead the L-stent is worse; In expansion, different connectors and axial supports of stent both have effect on flexibility of stent When the length of stents are equal, the number of axial support have a greater impact; when the number of axial supports are equal, the structure of connectors play a role in the flexibility of stents. No matter in pressure state or in expansion, the stent whose structure of connectors are round-arc has better flexibility than that whose connectors are straight. We studied the flexibility of coronary stents with different connection bars, provided scientific guidance for the design and development of the stent and interventional treatment.
  • YuTong Zhou;
    . 2014, 45(07): 9-0.
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    Using melt foaming process and gas injection foaming process, aluminum foams were produced seperately from A356 aluminium alloy. For gas injection foaming process, Al2O3 particles and SiC particles are both adopted. A comparison of microstructure between aluminum foams prepared by different methods was carried out, and the related causes of its formation were also analyzed. Results indicate that aluminum foams produced by different methods are distinct in constitutional phases, area fraction of diffierent phases, average size of primary aluminum, metamorphic grade of eutectic silicon and other aspects, which makes these two kinds of aluminum foams different in mechanical properties. Therefore, we should select suitable aluminum foam according to its actual application.
  • Pengfei JI;
    . 2014, 45(07): 10-0.
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    Based on the SiO2/Al-10Si reaction system, Al2O3 particle reinforced aluminum matrix composites was successfully prepared through the combined process of semi-solid mechanical stirring and high-energy ultrasound treatment. Pretreatment of SiO2 powder and activation of aluminum melt by Mg improve the wettability of each other. Under the condition of a 700r/min stirring speed and a 10min stirring time, uniform distribution of SiO2 particles can be obtained. After the temperature increased, a further step of the high-energy ultrasonic treatment to the melt followed, not only promoting the in-situ displacement reaction of SiO2 and Al, but also eliminating the residual gas by acoustic cavitation. The analysis through Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that in situ processed Al2O3 particles distributed uniformly in the aluminum silicon alloy matrix.
  • Ya-Wei HAN
    . 2014, 45(07): 12-0.
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    The hot temperature compression test of commercially pure titanium was carried out by Gleeble-1500D thermal simulation test machine to investigate the dynamic recrystallization behavior. The deformation temperatures were 700℃, 800 ℃, 900℃, 950℃. The strain rates were 0.01 s-1, 0.1 s-1, 1 s-1 and 5 s-1. Dynamic recrystallization critical condition was obtained by calculation of true stress-strain data from the experiment and the analysis of material microstructure after deformation. The results show that the dynamic recovery and recrystallization occur during thermal deformation process. Recrystallization critical strain decreases with the rise of temperature and the decrease of deformation rate when dynamic recrystallization occurs. It is reasonable to regard the infection point of lnθ-ε curve as material recrystallization critical strain. There is a relationship between dynamic recrystallization critical strain and peak strain: εc=0.485εp.
  • ;;;;;Liben Li
    . 2014, 45(07): 13-0.
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    Zn2SnO4 and BaTiO3 powers were synthesized via the solid state reaction, respectively. Zn2SnO4 doped BaTiO3 ceramics (ZS-BT) were prepared via traditional ceramic preparation process and their dielectric properties were studied. The results show that doping appropriate amount of Zn2SnO4 could promote the ceramic sintering, reduce the dielectric loss; With increasing Zn2SnO4 content, the curie peak of dielectric-temperature spectra for BaTiO3 ceramics were depressed and shifted to low temperature; In the temperature range of 40~125 ℃, the dielectric-temperature spectra (102~109 Hz) get flat and the BaTiO3 ceramics doped with 2% Zn2SnO4 exhibits a lowest dielectric constant change rate of less than 8%. These results suggest that ZS-BT ceramics has an important significance for researching temperature-stable ceramic capacitor materials.
  • ;
    . 2014, 45(07): 14-0.
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    At room temperature, ZnO Nanopartikel-Suspension was prepared by ultrasonic method in the dispersed system of water and hexane (19:1) with Zn which was processed by mechanical milling for 13 hours. Then, AgNO3 was photoredued to prepare ZnO/Ag nanocomposites. The XRD and TEM analyzed ZnO/Ag composite particles. The SEM and I-V tester tested ZnO/Ag composite thin films and electrical properties. The results of XRD and TEM show that ZnO synthesized by ultrasonic method is short rod-like with the wurzite hexagonal structure and length of about 20nm; the structure of Ag nano-particles on the surface of ZnO by photo-reduction method is face-centered cubic. The SEM and I-V results reveal that drying temperature has a great influence on the composite structure. When drying temperature is 60℃, the composite thin film has compact and uniform structure and break-over voltage is about 2V; when drying temperature is 100℃,the structure of the composite thin film is transformed into the Ag network of composites with ZnO branches and break-over voltage is about 0.02V. By controlling the drying temperature, combinations of ZnO with Ag in composite thin films and the electrical properties could be changed.
  • Juan LIZheng-Peng LIU;;;
    . 2014, 45(07): 15-0.
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    The mechanism of hydrogen plasma passivation for poly-Si thin films has been investigated. It has been found that different kind of hydrogen plasma radical is responsible for different defects passivation for poly-Si. The Hα with low energy is mainly responsible for passivating the dangling-bond defects. The H* with higher energy may passivate the defects related to Ni impurity around the grain boundaries more effectively. In addition, the Hβ and Hγ with the highest energy are required to passivate intra-grain defects. These analysis and results are very usable to optimize the H plasma passivation and make the passivation more effective.
  • . 2014, 45(07): 16-0.
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    Cu1.1Mn1.9O4 powder was prepared by solid reaction method and sol-gel method. The electrical conductivity of Cu1.1Mn1.9O4 powder was 30S/cm at 750℃, and a small amount of second phase was dissolved and precipitated from it in heating and cooling process when the temperature rising from RT to 800℃ or decreasing from 800℃ to RT. It showed a good chemical stability when Cu1.1Mn1.9O4 sintered with La0.8 Sr0.2 Mn O3 (LSM) for 500h at 500℃.
  • 工艺 技术
  • Yan Zhou;
    . 2014, 45(07): 17-0.
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    The variation of density and diameter of Te inclusions in Indium-doped Cd0.9Zn0.1Te(CZT) single crystals during annealing under Cd/Zn vapor were studied via IR microscopy observation. The results indicated that the density of Te inclusions distributed homogeneously before annealing, while after annealing, the density of Te inclusions increased for about one order near the surface, but decreased for one order inside, and the density increased gradually along the direction of temperature gradient. The diameter of Te inclusions was mainly between 1 μm and 25 μm before annealing, while those with the diameter <45 μm near the wafer’s surface and those <5 μm and >25 μm inside increased notably after annealing. The reason for the above variation is determined by Te inclusions migration along the direction of temperature gradient. And during the migration, Te inclusions grew via incorporating with those with similar diameter and Ostwald ripening among those with comparatively different diameter. But the ripening was not sufficient so that many smaller Te inclusions remained in the annealed samples.
  • ;Jun-Zhu Ma ;
    . 2014, 45(07): 18-0.
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    The gradient coating of Ni60/high aluminum copper alloy was prefabricated on 45# steel substrate by supersonic plasma spraying and induction remelting. The characteristics of organizational structure, the transformation of phase structure, element diffusion were analyzed by means of SEM and XRD. The results indicated that the mechanical adhesion is the main way between the matrix and Ni60 coating by the supersonic plasma spraying, The slight sinter properties appear at the interface between Ni60 / high aluminum bronze coating , the interface is the mechanical combination and mild metallurgical combination of hybrid combination way. The fully bidirectional diffusion fusion of Ni60 is appeared between the matrix and high aluminum copper alloy coating after the induction remelting. A metallurgical bonding is formed between the Ni60 and the matrix, whose structure is dense and seamless, and whose elements form gradient or uniform distribution. The integrate coating is formed which has not distinct metallurgical belt. The boundary between the Ni60 and the high aluminum copper coating disappeared. The diffused element in this coating distribute as the gradient form.
  • Long-Fei Chang; ;;
    . 2014, 45(07): 19-0.
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    This paper mainly focused on the manufacturing process for Pd-IPMC. In order to increase the electro-active displacement of Pd-IPMC, the main parameters in two core steps, the Impregnation–Reduction Plating (IRP) and the Autocatalytic Plating(ACP), were optimized with an orthogonal array method; And the influences of these parameters on the final displacement were analyzed. Optimized value, effect ranges and the effect curve for the manufacturing parameters are presented. In addition, Pd-IPMC manufactured with the optimized parameters presents significant improvement in the displacement and exhibits better performance than the Pt-IPMC as well as Pd-IPMC purchased from ERI. This research verified the feasibility of using Pd as electrodes for IPMC and greatly improved the unsatisfied performance of current Pd-IPMC; therefore, it will be of great significance for guiding the manufacture of low-cost, large-displacement IPMC materials and will promote their industrial application.
  • Yunxian Cui
    . 2014, 45(07): 20-0.
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    The preparation of the high insulativity of Al2O3 film is one of key technologies of film thermocouple transient temperature sensor. The flaws such as pinhole always exist on the Al2O3 film prepared by direct current (DC) pulsed magnetron sputtering. The Al2O3 insulating film for film thermocouple transient temperature testing sensor is prepared by DC pulsed magnetron sputtering adding RF bias. The measurements for the thickness, insulativity, surface morphology and membrane adhesion of the Al2O3 film are operated through the steps, megger, scanning electron microscopy and scratch tester. The results show that the film is uniform, and the surface is smooth. The thickness of Al2O3 film prepared with 9 h by DC pulsed magnetron sputtering adding RF bias is 2.4 μm. The insulation is 2.6×109Ω. The atom ratio of Al/O is 2:3 for all samples. The binding force with the metal substrate is 12 N. This article provides a kind of simple and effective method to preparate Al2O3 films, presenting high density, high insulation performance, which provides the technical support for the preparation of the transient temperature sensor.
  • Haibin Li; ;S.L. ZhuXian-Jin YANG
    . 2014, 45(07): 21-0.
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    Thermochemical treatments including gas nitriding, pack carburizing and carbonitriding were performed to modify the surface of Ti-6Al-4V alloy and prepare three kinds of surface layers on the surface of the alloy. Microstructure, composition and Vickers microhardness were characterized using SEM, XRD and Vickers microhardness test. Subsequently, cavitation erosion resistance of the surface layers was evaluated using an ultrasonic vibratory apparatus. The results showed that a dense and hard ceramic was formed on the surface of Ti-6Al-4V alloy. The strong ceramic layers can suppress the crack initiation at the surface and prohibit the crack propagation to the basic, and resulted in the reduction of the materials damage and increase in the incubation period and cavitation erosion resistance.
  • ; ;Xue-Yuan TANG;;ma-tai DING
    . 2014, 45(07): 22-0.
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    Silicon carbide fibers doped with iron of 0-2wt% are prepared from iron-containing polycarbosilane by using oxygen-curing method. The as-prepared fibers are heated in high purity argon from 700oC to 1100oC up to 100h. With the change of treating parameters, the specific resistivity of the fibers decreases from 13847 to 6 ohm.cm while the content and crystallinity of the multi-phases in fibers vary non-monotonically. Linear relationship between microstructure with electrical property is evaluated using Pearson coefficients. Among the tested factors, grain size of β-SiC is the most relevant to specific resistivity, effect of iron content is subordinate. Mechanism on microstructure evolution of the iron-doped fiber is proposed.
  • Ya LUO; ;
    . 2014, 45(07): 23-0.
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    It is tended to be burnt for alloying elements, strengthening particles are tended to aggregating during TIG in -situ welding for MGH956 alloy. In this paper, effects of heat treatment on TIG in-situ alloying welded MGH 956 alloys organization were studied. Filler material of ωV = 2.0% was added in the welding process, heat preservation time was 2.0 h, temperature was 700℃, followed by air cooling. After heat treated, the grain boundary aggregation significantly reduced, more fine dispersion of particles generated in the weld, which are mainly YAlO3, TiC and TiN particle by EDS analysis, in addition, (Ti, V) C composite particles were fund. By atomic probe analysis, the segregation of element Y reduced, thereby reducing the porosity of the weld after heat treatment, ultimately, performance of the joint improved.
  • Teng Teng ZHAO
    . 2014, 45(07): 24-0.
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    Abstract: Cr/Cu composite powder catalyst was prepared via a combination of in situ synthesis and chemical co-deposition (CVD), and was applied to the synthesis of carbon nanotubes. Techniques of X-ray diffraction (XRD), as well as scanning electron microscopy (SEM) and transmission electron microscope (TEM) had been employed to characterize the crystal phase, micro structural morphologies of the as-synthesized materials, respectively. The results show that the content of Cr had a significant effect on the structure of CNTs, and the catalyst with 10wt.%Cr is best. There are differences among materials calcined at different temperature, among which well-crystallized Cr/Cu nano-composite catalyst can be produced by calcined the precursor at 700℃.The quality and morphology of carbon nanotubes synthesized by different Cr/Cu composites calcined at various temperatures have great differences, and CNTs with high purity and smooth surface can be obtained when the catalyst at 800℃.
  • 研究 开发
  • . 2014, 45(07): 25-0.
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    In this paper, the as-solution microstructure of the AZ31, the Sr, Ca added, has been analyzed by the Scanning Electron Microscope and Optical Microscope. The results show that the Ca and Sr are beneficial to reduce the grain size. The grain boundary straight level during the solution treatment process is decreasing with the content of Ca increasing. It concluded that the Mg2Ca phase can restrain the grain boundary diffusion mobile. The AZ31 contained different Sr and Ca has also been extruded in this paper, the recrystallization grain size reduced when the content of calcium is increasing. However, the mother crystal is also existed in the matrix. When the content of calcium is increasing to 0.9wt.%, the Mg2Ca influence to the grain size is decreasing. The elongation of AZ31 is increasing with the content of calcium increasing. When the content of calcium is increasing to 0.6wt.%, the elongation is get to 29%. But when the content of calcium is increasing to 0.9wt.%, the elongation is lower than the 0.6wt.%.
  • 工艺 技术
  • . 2014, 45(07): 26-0.
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    The effects of different processing technology combined ECAP(equal channel angular pressing) and aging treatment on microstructure and properties of Cu-0.8Cr-0.15Zr alloy were investigated. The results showed that the microstructure of the alloy after 8 passes of ECAP was consisted of the equiaxed grains, and the average grains sizes were 200nm,the microstructure uniformity of alloy were improved even more after aging. Tests of mechanical and conductive properties at room temperature showed that the Cu-0.8Cr-0.15Zr alloy has strong aging strengthening effect and cold deformation before aging can greatly improved the properties of the alloy. the alloy that was aged at 420℃ for 3h after eight passes of ECAP has the best comprehensive properties with hardness, tensile strength, elongation and electrical conductivity of 249.15HV, 623.1MPa, 12.3% and 85.34%IACS. Grain-refining strengthening is dominant strengthening mechanism in ECAPed Cu-0.8Cr-0.15Zr alloy, as well as also the pinning effect of precipitates that the fine chromium and the second phase distributed in matrix on dislocations contribute to the improvement of strength.
  • Chun-Lin LI
    . 2014, 45(07): 27-0.
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    To clarify the effect of cooling mode on the damping capacity of Fe-16Cr-2.5Mo alloy, the specimens are annealed at 1100℃ in vacuum by 1 hour and cooled down in furnace, air and oil condition respectively. The relationships between the damping capacity, the microstructure and the internal stress of the alloy obtained by different cooling code are analyzed . The results show that the maximum logarithmic decrement would increase and the strain where the maximum logarithmic decrement appearing would decrease with the decreasing of cooling rate .This can be explained by introducing the SB theory, which elaborating the relationship between the ferromagnetic damping and the internal stress. The internal stress can block the motion of domain wall and thus deteriorating the damping capacity. Compared with being cooled in air and oil condition, the specimen cooled in furnace would accesses a smaller internal stress because the segregation of carbon near the grain boundary, the reduction of vacancy concentration and a smaller density of the grain boundary.
  • 研究 开发
  • . 2014, 45(07): 28-0.
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    Abstract: Effects of Li addition on the microstructure of Mg-3Al based alloys by optical microscope (OM)、scanning electron microscope (SEM) and X-ray diffractometer (XRD).The tensile properties of as-cast and as-extruded Mg-xLi-3Al alloys were conducted at ambient temperature on an electro-universal testing machine (Instron 5569). The results show that lithium content in Mg-Li alloy is a key factor affecting the microstructure and properties of this series alloys. When it is between 5.7%-10.3 wt.%, Mg-Li alloy exhibits two phases structure which consists of α (h.c.p.) Mg-rich and β (b.b.c.) Li-rich phases. The elongation of alloys improved signi?cantly with the increase of Li content and the as-cast LA113 alloy obtains the optimal elongation of 37.36%. But the tensile strength of as- extruded Mg-xLi-3Al alloys decrease of with the increase of Li content and the as-extruded LA53 alloy obtains the optimal tensile strength of 263.28MPa. As Li content increases, the second-phase particle Al12Mg17 transforms into LiMgAl2 in Mg-Li alloys.