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      20 October 2018, Volume 46 Issue 10 Previous Issue    Next Issue
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    REVIEW
    Research Progress in Environmental Barrier Coatings of SiC Ceramic Matrix Composites
    Qiao-mu LIU, Shun-zhou HUANG, Ai-jie HE
    2018, 46 (10): 1-8.   DOI: 10.11868/j.issn.1001-4381.2018.000230
    Abstract ( 1639 ( PDF (2165KB)( 958 Citation

    SiC matrix ceramic composites (CMC-SiC) are considered as the potential primary structural materials in advanced gas turbines because of their low density, good oxidation resistance and high-temperature strength. However, CMC-SiC suffers from serious degradation in the gas environments. With the protection of environmental barrier coatings (EBCs), CMC-SiC composites can be possibly applied as hot components with long lifetime in the aero-engine. The materials selection requirements, development history, preparation process, assessment technologies and characterization methods of EBCs materials system were introduced in this paper. The open problems of EBCs materials system such as high volatile rate, low operating temperature during service and low crystalline fraction, low density of the coatings during the preparation process were summarized and analyzed. The research goal and development direction in the EBCs system optimization, fabrication process development and evaluation and assessment platform were put forward.

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    Development of Photocatalytic Degradation of Organic Pollutants in Water
    Feng ZHOU, Xiang-hong REN, Jian-you LIU, Pin LIU
    2018, 46 (10): 9-19.   DOI: 10.11868/j.issn.1001-4381.2017.000972
    Abstract ( 1908 ( PDF (1811KB)( 1458 Citation

    The energy crisis and environmental pollution problem is increasingly serious on a global scale, however the rapid development of photocatalytic technology brings the dawn to solve the problem, and the photocatalytic materials system as a basic element has become the focus. The photocatalytic degradation of organic pollutants in water was focused in this article, and the development status of photocatalytic technology, nine types of photocatalytic materials and their properties, mechanism of action and the application of research, as well as modification methods of the materials were summarized. Finally, it was proposed that the materials still has the problems of low solar energy utilization, low quantum yield, and insufficient photochemical stability at the current stage, nevertheless the new material system of metal-organic framework (MOF) and the modification methods of micro/nano mesoporous, multi-hole composite, Z-scheme semiconductors provide a broader space for the exploration of photocatalytic materials.

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    Application Research and Progress of 0D, 1D and 2D ZnO Nanomaterials
    Feng YANG, Fei WANG, Ruo-fei JIA, Li-li YANG, Hui YANG, Lan LI
    2018, 46 (10): 20-29.   DOI: 10.11868/j.issn.1001-4381.2016.000868
    Abstract ( 1241 ( PDF (1759KB)( 679 Citation

    ZnO as a wide band gap semiconductor not only has excellent optoelectronic properties, but also contains rich 0D, 1D and 2D nanostructures.Based on the 0D, 1D and 2D ZnO nanomaterials, the research progress of main optoelectronic device application, including photocatalysis, gas detectors, solar cells, photodetectors, light emitting diodes, lasers, piezoelectric devices and resistive random access memory was narrated synthetically in this paper.The differences of three dimensions in optoelectronic application of ZnO nanomaterial were laterally comparatively analyzed, and the advantages of different dimensions in the optoelectronic devices were summarized, finally, the problems in the application of zinc oxide nanomaterials were also prospected, such as the difficulty to achieve p-type doping.

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    RESEARCH ARTICLE
    Fabrication and Evaluation of Mono-sized Fe-based Fe60Ni7.5Mo7.5P10C10B5 Metallic Glass Spherical Micro Particles
    Wei DONG, Wen-chang LI, Fu-min XU, Yang HAN, Wei ZHANG
    2018, 46 (10): 30-36.   DOI: 10.11868/j.issn.1001-4381.2018.000106
    Abstract ( 727 ( PDF (2787KB)( 181 Citation

    Fe-based metallic glass particle has an excellent application prospect in micro-forming field due to their special properties. Mono-sized Fe60Ni7.5Mo7.5P10C10B5 metallic glass particles with controllable particle diameters were prepared by pulsated orifice ejection method (POEM). The analysis of these obtained particles was carried out by optical microscope(OM), scanning electron microscope(SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC). The results show that the metallic glass particles prepared by POEM have the advantages of uniform particle diameter, high sphericity and consistent thermal history. The microstructure of particles is transformed from fully amorphous phase to crystal phase with increasing particle diameters. In the experimental conditions of this paper, the critical diameter for obtaining fully amorphous phase should be less than 285μm in Ar atmosphere. However, the particle with the maximum diameter of 383μm in He atmosphere also maintain amorphous phase. The critical cooling rate calculated by the theoretical model should be over 1300K/s.

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    Cooling Process of Titanium Alloy Blades After Combustion Using Three Dimensional Heat Flow Coupling Numerical Simulation
    Xian-ye LIANG, Guang-bao MI, Pei-jie LI, Jing-xia CAO, Xu HUANG
    2018, 46 (10): 37-46.   DOI: 10.11868/j.issn.1001-4381.2018.000182
    Abstract ( 679 ( PDF (5411KB)( 340 Citation

    In order to understand the cooling procedure of aviation engine blade after titanium combustion, the finite element method was used to simulate the temperature and fluid field of ROTOR37 model after combustion occurred with 550℃ fire proof titanium alloy(TF550 titanium alloy) and 600℃ high temperature titanium alloy(TA29 titanium alloy), respectively. The results show that the relative mach number influences the cooling procedure of blade, the cooling performance at the area of mach number about 0.7-1 is much higher than other area; compared with the leading edge, the cooling process of the tip is more complex, and the cooling rate is an order of magnitude lower than that of the leading edge. The difference of cooling temperature between TF550 titanium alloy and TA29 titanium alloy at tip combustion area is quite observable; and the maximum value occurs within the scope of 1000-2500K; the former is more than 100K lower than the latter, the value is reduced into 30K within the scope of 300-500K. The temperature distortion of the flow field would increase the intensity of the surge, the effect of combustion on the surge margin should be fully considered during the design of the blade.

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    Hot Deformation Behavior of Powder Metallurgy Ti-14Mo-2.1Ta-0.9Nb-7Zr Alloy
    Lin MA, Wei LI, Jiao-jiao BAI, Feng-ting ZHAO
    2018, 46 (10): 47-54.   DOI: 10.11868/j.issn.1001-4381.2016.000907
    Abstract ( 571 ( PDF (4732KB)( 217 Citation

    The new medical Ti-14Mo-2.1Ta-0.9Nb-7Zr alloy was prepared by powder metallurgy. The high temperature compression behavior and the dynamic recrystallization behavior of the alloy were investigated by hot compression tests. The tests were performed with a Gleeble-1500D simulator at 780-960℃ and stain rate of 0.001-1s-1 up to a deformation of 60%.The hyperbolic sine modified Arrhenius model, which included deformation activation energy Q and temperature T, was used to describe the hot compression deformation equation of maximum deformation resistance; and the material parameter function of α(ε), n(ε), Q(ε) and A(ε), was introduced to obtain the constitutive equations. The results show that the flow stress values predicted by the proposed model have a good agreement with experimental results, high value of correlation coefficient (R=0.99430) and low value of average absolute relative error (5.327%); the critical stress and critical stain for dynamic recrystallization (DRX) under different deformation conditions are accurately calculated based on the method of work hardening rate and the inflection points, which are determined by fitting a third order polynomial to the θ-σ and lnθ-ε curves. Then the mathematical models of critical stress versus Z parameter and the critical stress equations of dynamic recrystallization are deduced, the critical strain εc mainly concentrates in the 0.01-0.04 and the critical strains of dynamic recrystallization alloy under different deformation conditions change in tiny.

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    Crystal Orientation Evolution During Friction Stir Welding of 6082 Aluminum Alloys
    Liang-liang ZHANG, Xi-jing WANG, Xiao LIU
    2018, 46 (10): 55-59.   DOI: 10.11868/j.issn.1001-4381.2017.001011
    Abstract ( 787 ( PDF (3915KB)( 473 Citation

    The evolution of grain morphology, grain boundary characterization, misorientation distribution and texture in upper part of base metal and nugget zone during friction stir welding of 6082-T6 aluminum alloys was investigated by the electron backscattered diffraction (EBSD) technique. The results show that the grains of the base metal are refined due to the experienced plastic deformation and dynamic recrystallization; based on the Thompson tetrahedrons that are formed behind the pin, the (110)[001] Goss texture and (114)[22${\rm{\bar 1}}$] texture are formed firstly in nugget zone adjacent to keyhole. Those grains rotate along 〈110〉 crystallographic direction due to the stress introduced by the shoulder, leading subsequently to the formation of the (112)[11${\rm{\bar 1}}$] copper texture and (11${\rm{\bar 1}}$)[112] texture; the nugget zone located at a distance of 40mm from the keyhole experiences shoulder extrusion, thus, the plastic deformation degree becomes bigger and the [110] fiber texture consequently dominates in this region.

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    Multiaxial Low-cycle Fatigue Behavior and Life Prediction of 7075-T651 Aluminum Alloy Thin-walled Tubular Specimens
    Ya-jun CHEN, Chen-chen LIU, Yu-long CHU, Xiao-xiao SONG
    2018, 46 (10): 60-69.   DOI: 10.11868/j.issn.1001-4381.2018.000152
    Abstract ( 828 ( PDF (5946KB)( 347 Citation

    Tension-torsion fatigue tests with different loading conditions were carried out on 7075-T651 aluminum alloy thin-walled tubular specimens aiming at studying multiaxial fatigue failure of aviation aluminum alloy. With the decrease of equivalent stress amplitude, the multiaxial fatigue life increases. Under the same equivalent stress, the multiaxial fatigue life is prolonged as the stress amplitude ratio augments while the tension-torsion phase has little effect on fatigue life. Under high stress amplitude, the materials are mainly softened in the axial and torsional directions while the hardening and softening alternately occur under the low stress amplitude. The platform area of macro fracture decreases with the increase of stress amplitude ratio. The microscopic fracture exhibits the multiple crack sources outside the wall of the tube. Fatigue striations and secondary cracks can be observed in the crack propagation region. Mixed mode dimples appear in the instantaneous fracture region. Based on Basquin's criteria, a modified model was proposed, and fine life prediction results were obtained, with the life prediction values in 2X scatter bands.

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    Microstructure and Fatigue Property of MB8 Magnesium Alloy Cross Welded Joints with Ultrasonic Impact
    Bo-lin HE, Ming-ming JIANG, Ying-xia YU, Li LI
    2018, 46 (10): 70-76.   DOI: 10.11868/j.issn.1001-4381.2016.001439
    Abstract ( 584 ( PDF (3329KB)( 270 Citation

    Surface treatment was carried out on the weld toe of MB8 magnesium alloy welded joints with ultrasonic impact treatment(UIT) method. The Surface microstructure and the fatigue property of treated and as-welded MB8 magnesium alloy welded joints were investigated. The experimental results show that after ultrasonic impact treatment, nano-crystalline microstructure is obtained by UIT method. Under the condition of the cycle life of 2×106, the conditional fatigue limit of as-welded joints is 32.07MPa, and the conditional fatigue limit of treated joints is 41.88MPa, which is increased by 30.59% than that of as-welded. The fatigue fracture of as-welded joints occurs mostly in the defects of weld zone, and the fatigue fracture of treated joints occurs mostly in the heat-affected zone. The ultrasonic impact treatment can not only increase the fatigue life of the joints, but also can change the fracture position of the samples. In addition, the heat affected zone is also a weak area of the fatigue fracture of the MB8 magnesium alloy cross joints, which is greatly related with the coarse grains in the heat affected zone.

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    Microstructural Degradation and Tensile Properties of K465 Equiaxed-cast Superalloy After Short-time Overheating
    Xiao-tong GUO, Wei-wei ZHENG, Cheng-bo XIAO, Yun-rong ZHENG, Qiang FENG
    2018, 46 (10): 77-86.   DOI: 10.11868/j.issn.1001-4381.2018.000188
    Abstract ( 680 ( PDF (5539KB)( 478 Citation

    Turbine blades of aircraft engines may suffer serious degradation caused by overheating service exposures. In this paper, microstructure characteristics and tensile properties of K465 alloy, which is an equiaxed cast superalloy and widely used in turbine blades and vanes, were investigated after overheating treatment at 1180~1270℃. The microstructure before and after overheating was also examined and quantitatively characterized using SEM, XRD and physicochemical phase analysis. The relationship between microstructural degradation after overheating and tensile properties was investigated. The results indicate that primary γ' phase, carbides and grain boundaries are gradually dissolved in K465 alloy with increasing the overheating temperature; γ' phase distributed in the interdendritic region has a higher dissolution temperature than that in the dendrite core region due to a higher content of γ' phase forming elements. Incipient melting mainly occurs at the residual eutectic region and grain boundaries at 1270℃. The tensile properties are decreased significantly with increasing the overheating temperature, the yield strength was 439MPa at 1000℃ and dramatically decreased to 85MPa and 26MPa at 1180℃ and 1240℃, respectively. The tensile properties are mainly influenced by the dissolution behaviors of primary γ' phase and γ' film along grain boundaries as well as the influence of incipient melting.

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    Stacking Fault Energies of Single Crystal Nickel-based Superalloy and Its Influence on Creep Mechanism
    Hua-jin YAN, Su-gui TIAN, Xin-jie ZHU, Hui-chen YU, De-long SHU, Bao-shuai ZHANG
    2018, 46 (10): 87-95.   DOI: 10.11868/j.issn.1001-4381.2016.000711
    Abstract ( 824 ( PDF (2167KB)( 536 Citation

    By means of calculating stacking fault energy(SFE), measuring creep properties and contrast analysis of dislocation configuration, the influence of the temperature on the stacking fault energy and the creep mechanism of a single crystal nickel-based superalloy was investigated. Results show that there is a lower stacking fault energy(SFE) of the alloy at 760℃, and the deformed mechanism of the alloy during creep is the cubical γ' phase sheared by 〈110〉 super-dislocation which may be decomposed to form the configuration of (1/3)〈112〉 super-Shockley partials dislocation plus the super-lattice intrinsic stacking fault(SISF). But the stacking fault energy of the alloy increases with temperature, so the deformed mechanism of the alloy during creep at 1070℃ is the screw or edge super-dislocation shearing into the rafted γ' phase. The SFE of the alloy at 980℃ is in the middle value of the SFEs between 760℃ and 1070℃, the main deformed mechanism of the alloy during creep is the screw or edge super-dislocation shearing into the rafted γ' phase. And some super-dislocation shearing into γ' phase may cross-slip from {111} to {100} planes to form the K-W locks configuration of (1/2)〈110〉 partials plus the anti-phase boundary(APB). The K-W locks with non plane core structure may restrain the slipping and cross-slipping of dislocations to improve the creep resistance of alloy. Wherein, the lower strain rate during creep releases too less deformed heat to activate the dislocation in the K-W locks for re-slipping on {111} plane, which is thought to be the main reason of the K-W locks kept in the alloy during creep at 980℃.

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    Stress Measurement of Laser Cladding Remanufacturing Coating with Ultrasonic Nondestructive Evaluation
    Xiao-ling YAN, Yong CAO, Shi-yun DONG
    2018, 46 (10): 96-103.   DOI: 10.11868/j.issn.1001-4381.2016.001329
    Abstract ( 685 ( PDF (2888KB)( 243 Citation

    Based on acoustoelastic theory, stress measurement of laser cladding coating with Rayleigh wave was investigated.The acoustoelastic formula for evaluation of stress in laser cladding coating was simplified by means of Taylor series expansion method.Combined with the static load tensile test, acoustoelastic coefficients were determined.The results show that the variation rate of Rayleigh wave signal velocity in Fe314 alloy coating increases linearly with the increase of stress.When tensile stress is greater than 495MPa, the variation rate of Rayleigh wave signal velocity does not change linearly any more.Based on the analysis of ultrasonic propagation theory and microstructure of laser cladding coating, the changing rule of acoustoelastic curve and its influence mechanism on stress measurement were analyzed, the inhomogeneous deformation of anisotropic laser cladding coating is the main cause of the "wave-type" fluctuation of acoustoelastic curve in high stress stage.Results show that anisotropic tissue effect can affect the result of stress measurement; the penetration in laser cladding layers can be ignored. By fitting the acoustoelastic curve, anisotropic tissue effect factor is determined.The experimental results show the maximum relative error in stress measurement is 4.4%, the method can realize the nondestructive evaluation of the stress in laser cladding coating.

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    Influence of Vacuum Chamber Pressure on Microstructure and Properties of Tungsten Target Fabricated by Low Pressure Plasma Spraying
    Yue-ming WANG, Qiu-hao TANG, Zhi-qiao YAN, Fen WANG
    2018, 46 (10): 104-112.   DOI: 10.11868/j.issn.1001-4381.2017.001120
    Abstract ( 689 ( PDF (6429KB)( 433 Citation

    Planar and rotary tungsten targets were fabricated by low pressure plasma spraying (LPPS). The effects of chamber pressure on the relative density, oxygen content by mass, microstructure, micro-hardness and ultimate tensile strength(UTS) of tungsten targets were analyzed. In addition, the magnetron sputtering experiment of LPPS tungsten target was studied. As chamber pressure increased from 1.3×104Pa to 3.9×104Pa, tungsten powders were full melted and spread with decreased unmelted particles existing in the target, the oxygen content in the tungsten target slightly improved. At the same time, relative density, micro-hardness, and UTS of LPPS tungsten target increased up to maximum values as 97.2%, 377.8HV0.025 and 201.1MPa, respectively. However, oxygen content of tungsten targets increased significantly up to 0.71% with floc like W3O layer(about 200nm thickness) being formed at lamellar bonding interface as chamber pressure further increasing up to 6.5×104Pa. Instead, relative density, micro-hardness and UTS of tungsten target decrease for detrimental effect of oxygen content. Smooth, dense and continuous tungsten thin film with the thickness of about 300nm can be deposited by magnetron sputtering from LPPS tungsten target under chamber pressure of 3.9×104Pa. XRD spectra show that the tungsten thin film in body centered cubic structure grows preferentially along (110) direction. The uniform bombardment of sputter ion results in rapid sputtering and uniform reduction on the surface of tungsten targets during magnetron sputtering. The sputtering surface and cross section are even and smooth with the nano-scale sputtering spits being formed.

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    Carbon Nanotubes/Cellulose Composite Paper as Electrodes for Supercapacitor
    Wei CHEN, Xiao-gang SUN, Man-yuan CAI, Yan-yan NIE, Zhi-wen QIU, Long CHEN
    2018, 46 (10): 113-119.   DOI: 10.11868/j.issn.1001-4381.2017.000482
    Abstract ( 857 ( PDF (4554KB)( 412 Citation

    Whisker multiwalled carbon nanotubes (WMWCNTs) and multiwalled carbon nanotubes (MWCNTs) were synthesized via chemical vapor deposition (CVD), and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Raman spectroscopy. Paper fibers were used as matrix material, WMWCNTs and MWCNTs as functional material. Paper fibers were mixed with dispersed WMWCNTs and MWCNTs by speed-cutting procedure in water. Then the composite papers were fabricated by vacuum filtration method. The electrochemical performance of the supercapacitor was tested by cyclic voltammetry, galvanostatic charge/discharge. The testing results indicate the supercapacitor has a maximum capacitance of 120F/g at a scan rate of 1mV/s and has a specific capacitance of 51.5F/g at 0.4A/g. The maximum energy density and power density reach 63.7Wh/kg and 3.99kW/kg respectively in the current range of 0.4-1.4A/g.

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    Polyphenylene Oxide-based Nanofiber Separator Prepared by Electrospinning Method for Lithium-ion Batteries
    Ke-feng LI, Xiao-yan YIN
    2018, 46 (10): 120-126.   DOI: 10.11868/j.issn.1001-4381.2017.000464
    Abstract ( 675 ( PDF (3591KB)( 245 Citation

    To improve the high temperature safety and charge-discharge performance of lithium-ion batteries, a novel polyphenylene oxide-based nanofiber separator was facilely prepared by electrospinning method and investigated in lithium-ion batteries. Some investigations including morphology, microstructure, electrolyte wettability, thermal resistance and cell performance were carried out. The results demonstrate that the polyphenylene oxide-based separator with fiber diameter of 260 nm exhibits uniform porous structure (with average pore size of 500nm). The porosity is up to 74%, which is about one time higher than that of polyolefin separators. This separator also shows excellent electrolyte uptake (310%) and thermal stability at 150℃ for 60min.Cell performance tests show that the nanofiber separator exhibits better discharge performance and cycle performance compared with the commercial PE separator.

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    Highly Crystalline MIL-100 (Fe) Nanoparticles Prepared from Ferrous Salts and Applications in Photodegradation of Organic Dyes
    Xiang-yue LIU, Yu ZHANG, Chen WANG, Hui-ling MAO, Xuan DU, Hu CHENG, Jin-liang ZHUANG
    2018, 46 (10): 127-134.   DOI: 10.11868/j.issn.1001-4381.2018.000591
    Abstract ( 875 ( PDF (3143KB)( 449 Citation

    In order to prepare highly crystalline and stable metal-organic frameworks (MOFs) nanoparticles in a straightforward and low cost method, trimesic acid was depronated by three equivalent NaOH in water, and mixed with ferrous salts (e.g. FeCl2 and Fe(OAc)) solution under vigorous stirring for 24h at room temperature. The morphology and photocatalytic activity of the obtained MIL-100(Fe) nanoparticles were fully characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and UV-Vis spectroscopy. The results demonstrate that the MIL-100(Fe) nanoparticles exhibit excellent photocatalytic performance toward high concentrated Rhodamine B (RhB) and methyl orange (MO) organic dyes in the presence of H2O2 as a co-catalyst under UV light irradiation.

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    Preparation of Dendritic Mesoporous Silica and Its Antibacterial Properties of Loaded Nano Ag
    Lian-gen HUANG, Yu-ying ZHENG
    2018, 46 (10): 135-141.   DOI: 10.11868/j.issn.1001-4381.2017.001363
    Abstract ( 911 ( PDF (2847KB)( 711 Citation

    Dendritic mesoporous silica microspheres were prepared by sol-gel method with ammonium as catalyst, TEOS as silica source and CTAB as surfactant. Nano Ag was in-situ loaded in the SiO2 microspheres. The effect of different amounts of ether and silane structure promoter on the morphology, structure and particle size of dendritic mesoporous SiO2 microspheres was studied. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the samples were tested by antibacterial examination. The results show that the addition of silane structure promoter and ether is crucial to the formation of dendritic pores. The MIC of nano Ag in the mesoporous silica is between 3.16mg·L-1 and 3.95mg·L-1, the MBC is 6.32mg·L-1. Both of them are superior to pure nano Ag in antibacterial properties.

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    Effect of Heterogeneous Resin Curing Agent on Micro-mechanical Uniformity of Resin Matrix of Composites
    Miao-cai GUO, Xu-hui HONG, Ya-feng LI
    2018, 46 (10): 142-148.   DOI: 10.11868/j.issn.1001-4381.2017.000006
    Abstract ( 617 ( PDF (3577KB)( 219 Citation

    Preparation of prepregs by hot melt method is generally involved the infiltration of resin. For the epoxy resin with a heterogeneous curing system, the preparation of large thickness prepregs may be affected by the uneven distribution of curing agent. A nanomechanical method was used to study the micro-mechanical uniformity of the resin matrix of the composites prepared by thin thickness glass fibre prepregs and the glass fibre reinforced composites prepared by resin vacuum suction technology. The results show that to the composites prepared by thin thickness prepregs, the resin exhibits good micro-mechanical uniformity, the nano-hardness and wear properties of the resin at the different regions of the composite cross-section have a good uniformity. The composites prepared by resin vacuum suction method exhibits obvious layered distribution, the particles of the curing agent and accelerator are enriched at the outer surface of the fiber layer. The resin at the outer layer of the fibre layer has higher nano hardness and wear resistance, while to the resin about 0.4mm inside the fiber layer, its hardness goes down, a very low nano hardness of the resin deeply inside the fiber layer is observed.

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    Synthesis and Properties of High Temperature Resistant Poly (m-diethynylbenzene-methylsilane-phenylsilane) Resin
    Juan GE, Danibai SAILIKE, Quan ZHOU, Zheng-qiang PENG, Li-zhong NI
    2018, 46 (10): 149-155.   DOI: 10.11868/j.issn.1001-4381.2017.000385
    Abstract ( 563 ( PDF (2238KB)( 363 Citation

    Poly (m-diethynylbenzene-methylsilane-phenylsilane)(PDMP), the heat-resistant silicon-alkyne resin, was synthesized from m-diethynylbenzene, methylsilane and phenylsilane by the method of Grignard reagent. FT-IR, NMR and GPC were selected to characterize the structure of PDMP resin. The curing behavior was analyzed by DSC and rheometer, and heat performance was measured by TGA. The study shows that heat-resistant of resins first increases and then decrease with the increase of mole ratio of phenylsilane and methylsilane. When the mole ratio comes to 7:4, PDMP's heat-resistant is the best. And the Td5 (5% mass loss temperature) and residual are respectively 654℃ and 90.3% in N2, 574℃ and 34.0% in air after 1000℃.

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    Effect of Low-melting-point Curing Agent on Property of Epoxy Resin
    Zhi-dong REN, Chen-xi LIANG, Si-jia HAO, Yue XING, Jun-peng TIAN, Sheng-long DAI, Cheng YANG
    2018, 46 (10): 156-161.   DOI: 10.11868/j.issn.1001-4381.2017.001181
    Abstract ( 977 ( PDF (2044KB)( 783 Citation

    Effect of low-melting-point curing agent (MOEA) on property of epoxy resin was studied. The properties of epoxy resin (MOEA40) with MOEA as the curing agent were characterized and compared with the epoxy resin (DDM30) with 4, 4'-diaminodiphenyl methane (DDM) as the curing agent. The viscosity-temperature property, curing behavior, mechanical properties and thermal properties were characterized by rotational rheometer, differential scanning calorimetry (DSC), universal material testing machine, dynamic thermomechanical analyzer (DMA) and thermal gravimetric analyzer (TGA), respectively. The results show that MOEA40 has better viscosity-temperature property than that of DDM30. MOEA shows low viscosity (0.2-3.5Pa·s) in the temperature range of 60-140℃. MOEA40 and DDM30 are cured with the same curing progressing. Cured MOEA40 shows outstanding mechanical properties with bending strength about 147MPa and tensile strength about 89 MPa, which are 9.7% and 11.2% higher than that of cured DDM30 (bending strength 134MPa, tensile strength 80MPa). In addition, cured MOEA40 shows higher glass transition temperature (168℃) and higher thermal stability with 5% mass loss temperature about 367℃ in nitrogen atmosphere.

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