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      20 October 2012, Volume 0 Issue 10 Previous Issue    Next Issue
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    Influence of Cooling Methods on Microstructure and Creep Behaviors of HCR-GH4169 Alloy
    TIAN Su-gui, LI Zhen-rong, ZHAO Zhong-gang, CHEN Li-qing, LIU Xiang-hua
    2012, 0 (10): 1-7.  
    Abstract ( 599 ( PDF (3403KB)( 536 Citation
    By means of direct aging treatment, creep properties measurement and microstructure observation, the influence of cooling methods on microstructure and creep behaviors of HCR-GH4169 alloy has been investigated. Results show that, after directly aged treated, the "water cooling" HCR-GH4169 alloy possesses the fine grains in size, and significant amount of the γ',γ″ phases are dispersedly precipitated within the grain, which can enhance the creep resistance of the alloy. However, the bigger grain in size is displayed within the "air cooling" HCR-GH4169 alloy in which the amount of γ', γ″ phases decrease. Under the experimental condition, the "water cooling" HCR-GH4169 alloy possesses the longer creep lifetime. The deformation mechanisms of the direct aged HCR-GH4169 alloy are the twinning deformation and single or double orientations slipping of dislocations activated in the matrix. In the later stage of creep, the initiation and propagation of the cracks along the grain boundaries occur to promote the intergranular fracture of the alloy, which is thought to be the fracture mechanism of the HCR-GH4169 alloy during creep.
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    Influence of Temperature Parameters During Directional Solidification on Structure of As-cast Rhenium-containing Ni-base Single Crystal Superalloy
    CAO La-mei, YANG Xi-qiao, XUE Ming, CAI Qi-zhou
    2012, 0 (10): 8-11.  
    Abstract ( 679 ( PDF (1252KB)( 432 Citation
    The as-cast macrostructure and microstructure features for an experimental rhenium-containing (4.0%-5.5%(mass fraction)) Ni-base superalloy under different directional solidification conditions was investigated. And the effects of temperature parameters during directional solidification on the single crystal integrity, micro-porosity, (γ+γ') eutectic content and dendritic segregation were analyzed. The results indicate that the high melt superheating temperature not only promoted the homogenization of alloying elements, but also reduced the tendency to form defects in Ni-base single crystal superalloy containing both high Re and high levels of refractory elements. The melt feeding in the interdendritic region became more complete and the content of micro-porosity reduced with increasing the melt superheating temperature, mould temperature and casting temperature.
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    Prediction of Creep Rupture Property Using MHZ Constant for Heat Resistant Steel
    LIU Chun-hui, CHENG Cong-qian, ZHAO Jie, ZHU Zhi-chao, MA Hai-tao
    2012, 0 (10): 12-16.  
    Abstract ( 709 ( PDF (1854KB)( 314 Citation
    Manson-Haferd constants (Ta=450, lgta=15), which is named as MHZ constant, was proposed to correlate the creep rupture data. HP40 and Super304 heat resistant steels were taken as examples to describe the distinction of correlation between the creep rupture property curves based MHZ constant and L-M constant with experimental data. In order to analyze the applicability of MHZ constant to heat resistant steel, MHZ constant was applied to correlate the creep rupture data for seventeen steels widely used in industry, the corresponding prediction accuracy was compared with that based on recommended L-M constant. The result showed that the stress-rupture curves with different L-M constants steel are obviously different, which means that the L-M constant should be optimized to guarantee enough life prediction accuracy in the engineering components. However,a good agreement with the experimental data and high prediction accuracy has been achieved in the case of MHZ constant. Moreover, MHZ constant displays a relatively high resolution for creep rupture differences between various steels. It suggests that MHZ constant can be used as temperature-time-parameter (TTP) for heat resistant steel.
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    Corrosion Behaviors of Super 13Cr Martensitic Stainless Steel Under Drilling and Completion Fluids Environment
    LIU Ya-juan, LU Xiang-hong, ZHAO Guo-xian, CHEN Chang-feng, XUE Yan
    2012, 0 (10): 17-21,47.  
    Abstract ( 810 ( PDF (2896KB)( 389 Citation
    By simulating drilling and completion fluids environment,the performance of super 13Cr martensitic stainless tubular products against uniform corrosion,pitting,stress corrosion cracking (SCC) and acid liquid corrosion was studied. The results indicate that the uniform corrosion rate of super 13Cr martensitic stainless steel increases as the well depth increases. Further,the uniform corrosion rate of super 13Cr in gas phase is higher than the one in the liquid phase,but it is far less than 0.1mm/a both in liquid phase and gas phase corrosion conditions. Since super 13Cr martensitic stainless steel contained relatively higher Mo and Ni element,obvious pit corrosion and stress corrosion cracking did not occur under simulating corrosion environment. After the cyclic acid corrosion test,local corrosion including pitting,crevice corrosion,etc.,did not occur either on the pipe body or on the coupling.
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    Effect of Zn2+ Content on Microstructure and Magnetic Properties of Nanocrystalline Ni-Zn Ferrite
    WANG Jin-xiang, GAO Yan, YANG Yang, QIAN Qian, LIU Yin
    2012, 0 (10): 22-24,34.  
    Abstract ( 597 ( PDF (1190KB)( 516 Citation
    Nanocrystalline Ni1-xZnxFe2O4 ferrite with 0≤x≤1.0, was successfully prepared by spraying-coprecipitation method. The microstructure was investigated by using TG-DSC, XRD, TEM. Magnetic properties were measured with vibrating sample magnetometer (VSM) at room temperature. The results show that uniform and fine nanocrystalline Ni1-xZnxFe2O4 ferrite powders are obtained by spraying-coprecipitation method. The grain size is about 30nm calcined at 600℃ for 1.5h. There are a few agglomerates with average sizes below 100nm. Lattice parameters and the specific saturation magnetization of nanocrystalline Ni1-xZnxFe2O4 ferrite increase with the concent of Zn+2 at room temperature, and maximum Ms is 66.8 A·m2·kg-1 as the content of Zn2+ is around 0.5mol.
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    LEI Hai-bo, LUO Yun-jun, WANG Sheng-peng, LI Zhuo-xin, WANG Bao-yi
    2012, 0 (10): 25-29.  
    Abstract ( 633 ( PDF (1138KB)( 401 Citation
    In order to study the relationship between the structure and application performance of water-borne polyurethane modified by fluorinated polysiloxane(WFSPU), the phase separation characteristic,free volume hole size and surface elements of WFSPU film were investigated by dynamic mechanical analyzer, positron annihilating life spectrometer and X-ray photoelectron spectroscopy instrument respectively. The application performance of coated fabric including cohesive strength, moisture permeability, water repellency and elasticity were tested by using fabric strength tester, water resistance tester for fabric, water vapor permeability tester, contact angle meter and crease recovery angle tester. The results show that, compared with unmodified polyurethane, the microphase separation degree of modified polyurethane improved, size and percentage of free volume hole of polyurethane film increased, and some F, Si element migrated to film surface; as the AFS content increasing, The cohesive force between coating and fabric increased gradually, the moisture breathability of coated fabric increased first and then decreased, the hydrostatic pressure decreased gradually, the water repellency of coated fabric increased gradually, and the elasticity increased first and then decreased. In all, the performance of WFSPU was best when the mass fraction of AFS was 6%.
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    The Rheology of Solvent Based Polyacrylate Pressure Sensitive Adhesives
    ZHANG Xiao-wen, DING Yu-ting, ZHANG Guan-li, LI Lei, YAN Yue
    2012, 0 (10): 30-34.  
    Abstract ( 672 ( PDF (1284KB)( 468 Citation
    The rheology of solvent based polyacrylate pressure sensitive adhesives (PSA) with different molecular weight was studied, the rheological parameters were decided in frequency sweep, amplitude sweep patterns respectively, creep recovery properties were also studied, in this way, as the molecular weights of the PSAs were changed, the elasticity and the viscosity of the PSAs were systematically analysed, which were two of the most important properties of the solvent based polyacrylate PSAs. The results demonstrated that the cross-over frequency(f*) decreased while the zero shear viscosity(η0) and the elasticity increased as the molecular weight of the PSA increased; in amplitude sweep pattern, the linear viscoelastic range(LVE) and the elastic modules (G') and the viscous modules (G″) also increased as the molecular weight increased, however, the increment of the elastic modules was greater than that of the viscous modules, accordingly, it showed that G'< G″ at first and then G'=G″ and G'> G″ in the end as the molecular weights of the PSAs were increased, which meant that the rheological behaviours of the PSAs were shifted from viscoelastic fluid to viscoelastic solid; via the creep recovery test, it proved that the increase of the molecular weight plays an important role in the improvement of the creep recovery properties of the PSA, and the creep recovery time was obviously elongated.
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    Dynamic Mechanical Properties of Phenyl Silicone Rubber
    HAO Min, HUANG Yan-hua, SU Zheng-tao, WANG Jing-he
    2012, 0 (10): 35-38,53.  
    Abstract ( 861 ( PDF (1567KB)( 520 Citation
    The dynamic mechanical properties of the SE series phenyl silicone rubber under the different strain, temperature and frequency were characterized by rubber processing analyzer. The results show that with the increasing of strain the elastic modulus G' of the SE series vulcanized rubber decreases, that the tanδ increases slightly and that the viscous torque S″ of the SE series mixed compounds increases. The tanδ reduces with the increasing of temperature. With the increasing of frequency, tanδ of SE series mixed compounds decreases while tanδ of the vulcanized SE series increases; and tanδ of mixed compounds is much greater than vulcanizate’s.
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    Microstructural Evolution of TC11 Titanium Alloy at Rubbing Interface During Linear Friction Welding
    LANG Bo, ZHANG Tian-cang, TAO Jun, SUN Cheng-bin
    2012, 0 (10): 39-43.  
    Abstract ( 656 ( PDF (4631KB)( 363 Citation
    Microstructure of flash and joint was investigated using optical microscopy (OPM) and scanning electron microscopy (SEM) for understanding microstructure evolution of TC11 titanium alloy at the rubbing interface during linear friction welding. The results show that microstructure evolution of titanium alloy at the rubbing interface during linear friction welding contained four stages, that is, sliding friction and wearing, sticking and shearing friction, forming metallic bond and having a highly deformed microstructure, dynamic recrystallization in sequence. Temperature was uniform at the rubbing interface for sufficient friction time, and plastically deformed material was formed. That resulted in complete transformation of alpha to beta phase and then dynamic recrystallization of prior beta phase. The dynamic recrystallization grain size of prior beta phase would be greater with friction time rising due to higher temperature.
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    Investigation on the Fabrication and Properties of HGB/PLA Composites
    YANG Ji-nian, XU Ai-qin, DING Guo-xin
    2012, 0 (10): 44-47.  
    Abstract ( 584 ( PDF (1510KB)( 266 Citation
    The composites of poly (lactic acid) (PLA) filled with hollow glass beads (Hollow Glass Beads,HGB) were prepared by using molten blending and compression molding. The effects of HGB contents on the morphologies, mechanical properties and melt flow rate of HGB/PLA composites were investigated. The results show that well dispersed HGB in matrix and improved interfacial adhesion were observed between the PLA and HGB coated by silane coupling agent. With the increment of HGB, the specific tensile strength and elongation at break of HGB/PLA composites were increased first and then decreased; however, the specific elastic modulus exhibited the trend of continuous increase. The existence of HGB led to negative influences on the specific impact toughness, but brought on a remarkable positive impact on the melt flow rate of HGB/PLA composites.
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    Numerical Simulation of Solidified Microstructure of Twin-roll Continuous Casting Pure Aluminum Based on CA-FE Method
    CHEN Shou-dong, CHEN Jing-chao, LU Lian-hao
    2012, 0 (10): 48-53.  
    Abstract ( 686 ( PDF (1497KB)( 314 Citation
    The width of columnar grain zone in as cast strips is mainly determined by the length of columnar grains at nip point. Coupling temperature field, concentration field and micro growth, the simulation of the solidification structure on the solidification process of pure aluminum in water-cooled steel mould of twin-roll continuous casting was presented by CA-FE method in Procast. The model was built according to Cellular Automaton model and the locally functioned law of grain growth was established. By this model, the solidification of the single-phase pure aluminum was simulation and studied on the grain scale. By use of this model,the effects of process parameters on the solidification structure were studied. The calculation results fit the experimental ones well, and then the validity and the applicability of the model were tested.
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    Influence of Processing Parameters on Void Content in VARI Manufacturing Techniques
    GUO Ming-en, SUN Zu-li, BIAN Wen-feng, SONG Xiao-ran, LUAN Gui-qing
    2012, 0 (10): 54-57,62.  
    Abstract ( 773 ( PDF (1672KB)( 359 Citation
    Through the experiments of VARI for making E-glass/vinyl ester composites, the influence of processing parameters on the content of voids in composite laminates was investigated and the condition of void formation was analyzed. The processing parameters including the temperature condition and vacuum pressure were studied. The result showed that the influence of vacuum pressure level on the content of voids in composite laminates was obvious, and the content of voids is lower at 80-90kPa.The influence of temperature level on voids content was notable below 20℃. Two trends are clear from experiments for the VARI process. First, the percentage of voids is higher near the vent as compared to the inlet. The second trend is that the void percentage increases through the thickness, being low near the plastic vacuum bag side and high near the mold tool side.
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    Preparation and Properties of Size Controlled Hydrophobic Polyphosphazene Micro-nano Spheres
    CAI Dan, WANG Yan, JIANG Zhen-hua, MU Jian-xin
    2012, 0 (10): 58-62.  
    Abstract ( 596 ( PDF (3639KB)( 347 Citation
    Artificial hydrophobic surfaces have generally been produced in two ways: to create a surface with micro-or nanosized roughness and to modify the surface with materials of low surface free energy. The fabrication of superhydrophobic surfaces using a simple and rapid method is a continuous demand. Polyphosphazenes are a versatile class of hybrid organic-inorganic materials which have remarkable properties and multiple applications. This paper prepared novel fluorinated cross-linked size controlled hydrophobic polyphosphazene micro-nano spheres by precipitation polymerization from hexachlorocyclotriphosphazene(HCCP) monomer.
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    Effect of Initial States on Creep Aging Behaviors and Mechanical Properties of 2124 Aluminum Alloy
    ZHAO Jian-hua, CHEN Ze-yu, LI Si-yu, YANG Jin-long, DENG Yun-lai
    2012, 0 (10): 63-67,72.  
    Abstract ( 581 ( PDF (2171KB)( 406 Citation
    Creep aging behaviors and mechanical properties of 2124 aluminum alloy sheets have been studied by optical microscopy (OM), transmission election microscopy (TEM), creep and tensile test, et al. The results show that when the creep aging at 185℃/150MPa, the turning point between the first stage and the second one along the creep curve is easily observed for the samples with an initial state of solution-water quenching (QCA), the characters of TEM micrographics show that the dislocation multiplication (DM) and the balance between DM and dislocation annihilation (DA) occur. While the turning point along the creep curve is difficultly identified for the samples with the initial state of solution-water quenching- rolling to thickness reduction rate of 8% (PCA), the microstructures of TEM reveal that DA mainly occurs. During the processes of creep-aging, it is found that the precipitating S' phase particles always nucleate with dislocation lines, and their orientations are effected by characteristics of dislocation moving. During PCA process, the existing of dislocation tangling by the rolling before the creep aging supports precipitating S' phase on vertical {210} planes, therefore, the stress orientated effect of S' phase is restrained. The mechanical properties of PCA sample are well than that of the as T6 and T87, and the anisotropy of mechanical properties is less than that of the as QCA.
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    Welding Properties of High Heat Input-welding for Mg-Treated Oil Tank Steel
    LIANG Guo-li, WU Hui-bin, YANG Shan-wu, LIU Xue-li
    2012, 0 (10): 68-72.  
    Abstract ( 545 ( PDF (1780KB)( 278 Citation
    It is based on the Mg-treated oil tank steel to study the effects of trace Mg element on impact toughness of coarse grain heat affected zone(CGHAZ) which was experienced the high heat-input welding cycle using Gleeble3500 combined with SEM, TEM and other experimental methods. The results showed that the pattern and distribution of inclusions happened to change Mg-treated oil tank steel with 690MPa level,the intrinsical inclusions of aluminum oxide and sulfide were converted to the inclusions contained Mg which is very fine and dispersion, the properties of base material and HAZ are all improved. The M-A island component of oil tank steel adding trace Mg coarseded with the heat input increase, the area percentage of M-A island component increased with heat input increase which led to the low temperature toughness worsen.
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    Hydrothermal Synthesis and Photochromic Characterization of Mo Doped WO3 Nanomaterial
    ZHOU Yan, ZHANG Ran, WANG Dong-sheng, YANG Bin
    2012, 0 (10): 73-79,83.  
    Abstract ( 695 ( PDF (3910KB)( 294 Citation
    WO3 is a multi-functional semiconductor, and photochromism is one of the most important characterizations WO3 owns. This work has established a facile method to synthesize Mo doped hexagonal WO3 using W powder, Mo powder and hydrogen peroxide as starting agents and adding Na2SO4 as a mineralizer. The morphology, size, phase structure and component were characterized by applying SEM, XRD, HRTEM, XPS, etc, and it is confirmed that Mo is successfully doped into WO3 as MoxW1-xO3. After irradiated with Xe lamp, the novel MoxW1-xO3 material holds much better photochromic phenomenon than pure WO3. The involved smaller band gap resulted in the more electron produce after irradiation. Moreover, by doping Mo, the electron transfer in this special structure is highly enhanced.
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    Effect of Heat Treatment Process on Microstructure and Mechanical Property of X80 Bend Pipe
    WANG Wei-guo, LI Yan-min, WEI Qin-wen, YAO Deng-zun, YIN Zhang-hua
    2012, 0 (10): 80-83.  
    Abstract ( 691 ( PDF (2528KB)( 281 Citation
    The effect of different heat treatment processes on microstructure and mechanical property of X80 bend pipe was studied. By the comparison of two different heat treatment processes, the effect of heat treatment for the microstructure and mechanical property of X80 parent material and weld was discussed. The result showed that the microstructure and mechanical property of X80 bend pipe was seriously affected by the heat process. By the heat process of 950℃ quench+500℃ tempering, the microstructure of heat-affected zone(HAZ) and girth weld had been refined. Furthermore, the toughness and the micro-hardness of the pipe steel and the girth weld had been improved, which indicated that the heat process of 950℃ quench+500℃ tempering is suitable for the production of X80 bend pipe.
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    Process and Surface Quality of Injection Molded Boron Carbide Nozzle with Micro Multi-holes
    WANG Chang-rui, LU Zhen, ZHANG Kai-feng, WANG Zhen-long
    2012, 0 (10): 84-88.  
    Abstract ( 729 ( PDF (1828KB)( 322 Citation
    Boron carbide nozzle with micro multi-holes was fabricated by powder injection molding. The effects of injection molding, debinding, sintering on microstructure and forming quality of boron carbide nozzle were investigated. The results show that boron carbide nozzle can be filled completely with appropriate molding parameters in mold temperature of 60℃, injection pressure of 100 MPa and nozzle temperature of 175℃. Cracks and warps are not found on the surface of debound product. Densities and linear shrinkages of boron carbide nozzle begin to increase and then decrease with the increasing of sintering temperature, however, the values of surface roughness begin to decrease and then increase. Boron carbide nozzle achieves the best forming and mechanical performances after sintering at 1950℃ of which the density, linear shrinkage, Vickers hardness and value of surface roughness are 97.1%, 18.7%, 3580HV and 6.17μm, respectively.
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    Research on Coating Microstructure and Corrosion Behavior of Galvanized Zn-Al-Mg Coated Steel Sheet
    LU Jia-shun, LI Feng, YANG Hong-gang, KANG Yong-lin
    2012, 0 (10): 89-93.  
    Abstract ( 941 ( PDF (4694KB)( 751 Citation
    Galvanized Zn-Al-Mg coated steel sheet offer higher corrosion resistance than conventionally galvanized steel because aluminum magnesium has a positive effect on the corrosion resistance of steel coating. In this research, Galvanized Zn-Al-Mg coated steel sheet was prepared in laboratory by hot dip simulator. By SEM and EDS, the surface and cross section microstructure Zn-Al-Mg coating was analyzed. The distribution of elements in coating includes Zn, Al, Mg and Fe was observed by EPMA. The anti-corrosion capability of Zn-Al-Mg coating was studied by salt spray test. Coating itself and the erode production was inspect by X-ray diffraction. It was proved that the Zn-Al-Mg coating has finer microstructure, and has even more excellent corrosion resistance. The protection mechanism of Zn-Al-Mg coating steel sheet in salt spray test was analyzed.
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    Evolution of Surface Properties for Plasma Treated Wood/Polyethylene Composites Under Water Soaking
    TAO Yan, WANG Hui, DI Ming-wei
    2012, 0 (10): 94-98.  
    Abstract ( 659 ( PDF (1836KB)( 310 Citation
    The surface of wood/polyethylene (PE) composites was treated by low-pressure glow discharge of air plasma to improve its adhesion properties. To explore the failure mechanism in the condition of water for the bonding joint, the ATR-FTIR and XPS were employed in the soaking experiment to investigate the effect of water on the surface properties of plasma treated wood/PE composites. The ATR-FTIR analysis results showed that the polar groups such as -OH, C-O and C=O were formed on the surface of the composites after plasma treatment. And the number of -OH, C-O and C=O groups on the surface of plasma treated wood/PE composites decreased firstly and then increased with the soaking time extended. The XPS analysis results indicated that the content of oxygen element in the composition of surface element for Wood/PE composites increased after plasma treatment. And the content of carbon element in the treated wood/PE composites surface increased firstly and then decreased and the oxygen element decreased firstly and then increased with the soaking time and the value of O/C descended firstly and then increased. The changes for the surface chemical groups and chemical elements of the plasma treated wood/PE composites would have a considerable effect on the durability of the bonding joint under water soaking.
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