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      20 January 2012, Volume 0 Issue 1 Previous Issue    Next Issue
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    Comprehensive Application of Material Database System in Material Selection Evaluation
    GUO Qi-wen, CAI Hong-nian, WANG Fu-chi, ZHANG Hong-mei, YANG Chun, CHENG Jian
    2012, 0 (1): 1-4.  
    Abstract ( 1078 ( PDF (1264KB)( 672 Citation
    The material selection evaluation based on material database can bring database full play in the mass memory and the powerful search function, and can give computer full play in the supercomputing power. Since such, the old complex process, which is the selection of the evaluating material and mass data initialization and model calculation, becomes shortcut, exact, simple and intelligent. On the base of the material database system construction, the functional module of the material adaptability evaluation method was developed, and the computer aided selection evaluation of material based on the material database was realized. This is a beneficial try in the direction of the material database system intelligent development. The attained quantified evaluation results directly reflect the difference between the close property and different property of the material selection schemes. The subjectivity and blindness which are generated when the material selection is only based on the experience decrease.
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    Microstructure and Mechanical Performance of AlCoCrNiSix Highentropy Alloys
    LIU Shu-qian, HUANG Wei-gang
    2012, 0 (1): 5-8.  
    Abstract ( 1153 ( PDF (3403KB)( 403 Citation
    The effects of Si contents on the variation of phase structure, microstructure characteristic and mechanical properties of AlCoCrNiSix highentropy alloys were characterized respectively by using of XRD, SEM, EDS and microhardness testing. The results reveal that alloys phase structure is transformed from the single bcc1 phase structure to the mixed bcc1+ bcc2 phase structure with the increase of Si contents. The bcc1 is an AlNi solid solution structure and the bcc2 is CrSi solid solution structure. The ascast microstructure of alloys has a change from the dendritic crystal morphology to the cellular crystal morphology with the Si content increasing. Al and Ni elements mainly exist in the dendritic crystal and Si element segregates in the interdendritic region within the ascast microstructure. The Si element plays an important role in the increasing hardness of the AlCoCrNiSix alloy significantly, the highest microhardness is up to HV991.
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    Phase Analysis of CrFeCoNiCu High Entropy Alloy
    REN Ming-xing, LI Bang-sheng
    2012, 0 (1): 9-12.  
    Abstract ( 1266 ( PDF (3337KB)( 465 Citation
    The identification of phase for CrFeCoNiCu high entropy alloy was performed by the analysis for phase diagram and observation for microstructure using high resolution SEM and TEM. The results show that the microstructure consists of simple dendrite and interdendritic structures containing nanoprecipitates. The constituent phases include the FCC solid solution phase of Fe, Cr, Ni, Co in the dendrites, the amorphous phase and FCC solid solution phase of Cu and Ni in the interdendrites. The phase diagram analysis shows that two phase transformations exist at the temperatures of 1400℃ and 1100℃, and microstructure of CrFeCoNiCu highentropy alloy is formed.
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    Distribution Characteristics of Mg17Al12 in Semicontinuously Cast AZ61
    FENG Zhong-xue, PAN Fu-sheng, ZHANG Xi-yan, TANG Ai-tao, FU Qi-tao
    2012, 0 (1): 13-17.  
    Abstract ( 1006 ( PDF (1511KB)( 538 Citation
    Quantitative characteristics of the average size and the area fraction of Mg17Al12 phase were investigated in the center and the edge of the semicontinuously cast AZ61 alloy ingot by image analyzing technique. The differences of the morphology and the distribution of Mg17Al12 phase in the surface and the center regions were observed by optical microscopy (OM) and scanning electron microscopy (SEM). The result shows that the morphology of dendrite controls the morphology and the distribution of Mg17Al12 phase, the more highly developed dendrite, the finer and the more disperse particles of Mg17Al12. The Mg17Al12 is finer and more disperse in the center region compared to the surface of the ingot and distributes mainly in the interdendritic area. However, in the surface region most of the Mg17Al12 particles cluster exhibits on grain boundary and this is contrast with the result of the permanent mould casting. The proportion of Mg17Al12 phase in the eutectic increases with the cooling rate and it is larger in area fraction in the surface region than that in the center of the ingot. In addition, the backdiffusion in the solid has an effect on the area fraction of Mg17Al12 in the center of the ingot.
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    Interface Bonding of AZ31 Magnesium Alloys During Accumulative Rollbonding
    ZHAN Mei-yan, LI Chun-ming, ZHANG Wei-wen, ZHANG Da-tong
    2012, 0 (1): 18-24.  
    Abstract ( 725 ( PDF (6397KB)( 506 Citation
    Interface bonding mechanism of AZ31 magnesium alloys during accumulative rollbonding (ARB) was studied by scanning electron microscopy. The results indicate that a good bonding is achieved during ARB by 50% thickness reduction at 300℃ and the subsequent rolling improves the bonding of interfaces introduced in the previous cycles. The ARB specimens show a typical ductile fracture with dimples and shear zones even at the bonded interface. When bonding is insufficient, the fracture surfaces are characterized by microcracks. Interface bonding process during ARB consists of two opposing brittle surface layers being deformed and broken up, underlying metals being exposed and extruded under the action of normal rolling pressure through widening cracks in the surface layers and contacting with each other. Bonding quality can be improved by annealing after ARB.
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    Corrosion Behavior of X80 Steel in Different Simulated Soil Solution
    WANG Ying, YU Hong-ying, CHENG Yuan, SHAN Hai-tao, SUN Dong-bai
    2012, 0 (1): 25-28.  
    Abstract ( 782 ( PDF (1692KB)( 454 Citation
    The corrosion behavior of X80 steel in three kinds of simulated soil solution, was investigated by methods of mass loss measurement, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and Xray diffraction (XRD). The results show that X80 steel is uniform corrosion in simulated solution of Shanshan and Xinzhou soil, and pitting corrosion occurs on X80 steel in simulated solution of Zhangshu soil. The ranking of the corrosion rate of X80 steel in different simulated solution is Zhangshu, Xinzhou and Shanshan. The saltcrystallization of CaSO4?2H2O, which could inhibit the erosion effects of Cl- and dissolved oxygen on X80 steel, continuously deposit on the surface of corrosion products in Shanshan simulated solution, and slow down the uniform corrosion rate as well. However, the corrosion product layer that could not provide effective corrosion protection for X80 steel in Zhangshu simulated solution, makes the corrosion of X80 steel become more serious with the increasing of immersion time, and finally results in pitting corrosion of X80 steel.
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    Insitu Synthesized Nb2(C,N) and V8C7 Ceramics Particulates Reinforced Febased Composite Coating by Laser Cladding
    LI Gui-hua, ZOU Yong, ZOU Zeng-da, WEI Xi-wang, TIAN Bao-lin
    2012, 0 (1): 29-33.  
    Abstract ( 813 ( PDF (2308KB)( 410 Citation
    Febased composite coating reinforced by insitu synthesized Nb2(C,N) particulates was prepared by 5kW CO2 laser equipment on 42CrMo steel. Microstructure and properties of laser coating were analyzed. The results show that the microstructure of coating consists of αFe,γFe phase,Nb2(C,N) and V8C7. Reinforcing ceramics particulates with granuliferous morphology are uniformly distributed in the Febase composite coatings which posses the better oxidation resistance. The wear mass loss of the coating is about one eighth of the 42CrMo substrate. The wear test shows that these reinforcement particulates improve significantly hardness and wear resistance of the coatings. The experimental results of oxidation resistance show that the structure of oxide scale in the coatings is continuous and dense, oxidation scales are about one eighth of the 42CrMo substrate through 750℃ constant temperature oxidation after 120h.
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    Effects of Hollowness on Properties of Hollow Phenolic Fibers
    ZHANG Dong-qing, GUO Quan-gui, SONG Yan, ZHAI Geng-tai, LIU Lang
    2012, 0 (1): 34-37.  
    Abstract ( 621 ( PDF (1609KB)( 308 Citation
    Hollow phenolic fibers with different hollowness were prepared by controlling thickness of the partiallycrosslinking spun filament derived from meltspinning of the phenolic resin. Section morphology,mechanical properties, high temperature properties and thermal insulation of hollow phenolic fibers with different hollowness were charactered by SEM, fiber strength tester, TGDSC and thermal insulation tester. The results show that shell thickness, apparent mechanical properties, degradation temperature and char yield decrease, mechanical properties change little and thermal insulation increases quickly with the degree of hollowness increase.
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    Nondestructive Evaluation for Thickness of Laser Cladding Coating Based on Surface Acoustic Wave
    LIU Bin, DONG Shi-yun, XU Bin-shi, HE Peng
    2012, 0 (1): 38-41.  
    Abstract ( 734 ( PDF (1334KB)( 376 Citation
    In order to settle the problem for measuring the thickness of laser cladding coating by nondestructive method, the surface acoustic wave was used according to the properties of surface acoustic wave in material. The crosscorrelation function, which was usually used to calculate the difference in time of flight between two different signals, was used. The results show that the propagation velocity of surface acoustic wave in laser cladding coating is faster and faster with the thickness of coating increasing, and by using crosscorrelation function for calculating the difference in time of flight, the curve between thickness of coating and difference in time of flight, which can be used to measure the thickness of laser cladding coating, is calculated, and the fitted result, which could be used to measure the thickness of coating, is obtained by using cubic polynomial. At last, the fitted result of cubic polynomial was proved by laser cladding coating with different thickness, and the influences that affected the experimental result were analyzed. The results show that the method that is represented can be used to evaluate the thickness of laser cladding coating.
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    Corrosion Behavior of Ultrahigh Strength Steel 23Co14Ni12Cr3Mo in Simulated Seawater Environment
    YU Mei, DONG Yu, WANG Rui-yang, QI Jin-yu, LIU Jian-hua, LI Song-mei
    2012, 0 (1): 42-50.  
    Abstract ( 996 ( PDF (0KB)( 1113 Citation
    The corrosion behavior of ultrahigh strength steel 23Co14Ni12Cr3Mo was investigated by three accelerated corrosion methods, alternating immersion corrosion, neutral salt spray and full immersion tests, and electrochemical impedance spectroscopy in simulated seawater environment. The morphology of corrosion products was observed by SEM and the composition was analyzed by Xray diffraction. The results show that the corrosion product layer is composed of outer rust layer γFeOOH and inner rust layer αFeOOH. The corrosion process begins with pit corrosion, then the corrosion area expands and the uniform corrosion forms with the corrosion time. The corrosion of extend is worst alternating immersion corrosion test, simulated alternation of wetting and drying seawater environment.
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    Experimental Study on Creep Characteristics of Sandwich PUEPM Core Under Static Pressure of Deep Water Environment
    YANG Kun, MEI Zhi-yuan, LI Hua-dong
    2012, 0 (1): 51-54.  
    Abstract ( 648 ( PDF (1473KB)( 356 Citation
    According to the elasticity theory,comparing the core material mechanical states in the sleeve under static pressure and the core mechanical states in the sandwich structure under deep water static pressure environment, the bushing test method adapted to study the creep characteristics of viscoelastic core materials was presented. The quasistatic compression and bushing compression creep tests for three different microspheresreinforced polyurethanemodified epoxy resin sound absorption materials (PUEPM) were carried out, the creep behavior of the core materials was obtained. The results show that the delaminated PUEPM core with low content glass microsphere and high content chopped fiber has preferable creep performance. The PUEPM core with higher content glass microsphere has higher resilience performance. The PUEPM core of type B has better comprehensive mechanical properties.
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    Microstructure Features of Insitu SiCp/6061Al in Plasma Arc Welding by New Reinforced Phase
    LEI Yu-cheng, LIU Zhen-zhen, XUE Hou-lu, HU Wen-xiang, CHEN Xi-zhang, YAN Jiu-chun
    2012, 0 (1): 55-58.  
    Abstract ( 755 ( PDF (2174KB)( 349 Citation
    The aluminum matrix composite which reinforced by SiCp particles was added Al5Ti5Si as filling material in plasma arc “insitu” welding, and the alternating arcultrasonic was needed in the welding process. The microstructures at the interfaces were observed by transmission electron microscopy(TEM)and HRTEM.The results show that the sizes of all new reinforced phases become smaller, and such orientation relationships as Al3Ti(020)∥Al(002), Al3Ti[001]∥Al[100] and AlN[100]∥Al[100] are founded in the joint. There are entirecoherent interface between the Al matrix and the small new reinforced phases of Al3Ti, AlN, Si and TiC, but no resultant production is observed along those interfaces. The Al matrix can grow along the new reinforced phases which have lowdislocation with Al, so the size of Al can be reduced. The mechanical testing results show that the maximum tensile strength of the welded joint is 92.69MPa, which reaches the 62% of the matrix strengths.
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    Simulative and Accelerative Experimentation of Carbon Steel Corrosion in Soil
    NIE Xiang-hui, LI Xiao-gang, LI Yun-long, LI Ji-ke, ZHANG Hong-bo
    2012, 0 (1): 59-65.  
    Abstract ( 779 ( PDF (2710KB)( 442 Citation
    Three soil corrosion simulative and accelerative experiments such as constant temperature and water content, alternative temperatures and alternative water contents of the Q235 carbon steel were conducted in seashore salt soil. The results indicate that the corrosion morphology of the carbon steel in soil with 10%(mass fraction)water content shows localized corrosion at the beginning, and turns to uneven general corrosion with time. For other experimental conditions, its morphologies are mainly uniform corrosion. The corrosion rate at 70℃ is higher than that at 50℃, and reaches to maximum at the same temperature when the water content is 10%. For constant temperature and water content experiment, its corrosion potential increases with time. Its corrosion potential and redox potential increase with water content and temperature decreasing in the alternative temperatures and alternative water contents experiments.
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    Tensile Property and Fracture Surface for MgAlZnY Alloys at Different Strain Rates
    LIANG Hao, CHEN Yong-mei, HU Wen-jun, FENG Jie, TAN Yun
    2012, 0 (1): 66-70.  
    Abstract ( 711 ( PDF (14472KB)( 354 Citation
    The tensile tests were conducted at room temperature using material test machine.The sensitivity of flow strength to strain rate was researched at strain rates of 0001, 01, 06s-1 for Mg3Al1Zn2Y, Mg3Al2Zn2Y and Mg3Al6Zn2Y. The sensitivity sequence of flow strength is Mg3Al2Zn2Y>Mg3Al1Zn2Y>Mg3Al6Zn2Y. The rupture characteristics of magnesium alloys were described based on the fractal theory and technology of computer image disposal combined with scanning electron microscope.The results show that the fractal behavior of the alloys’ fracture surface is remarkable. The brittleness, plasticity and the appearance of fracture surface can be related by the fractal dimension.The higher the fractal dimension, the better the alloy’s plasticity, the more complex the fracture surface and the alloy inclines to ductile rupture. The sensitivity sequence of fracture surface to strain rate is Mg3Al2Zn2Y> Mg3Al6Zn2Y>Mg3Al1Zn2Y with positive or negative effect.
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    Microstructures and Properties of 7050 Aluminum Alloy Sheet During Creep Aging
    CHEN Yuan-qing, DENG Yun-lai, WAN Li, JIN Kun, XIAO Zheng-bin
    2012, 0 (1): 71-76.  
    Abstract ( 1032 ( PDF (3283KB)( 368 Citation
    Microstructures and properties of 7050 aluminum alloy sheet after creep aging and artificial aging were studied by optical microscopy (OM), transmission electron microscopy (TEM), electronic tensile test and exfoliation corrosion test respectively. The results show that the loaded stress during creep aging generates continuously deformation, which provides a large amount of nucleation points for the precipitation of the η′ particles. The size of the η′ particles is smaller than that of the artificial aging. Especially, the precipitation free zone is narrower than that of the artificial aging, and grain boundary precipitates are discontinuous. The tensile strength and the resistance to exfoliation corrosion of the creep aging samples are better than those of the artificial aging.
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    Preparation and Properties of Microcapsules Containing αolefin Drag Reducing Polymer with Poly (Ureaformaldehyde) as Shell Material
    LI Bing, YU Ping, DAI Xiao-dong, XING Wen-guo, DONG Gui-lin, ZHOU Ning-ning, QIN Zhan-bo, ZHANG Chang-qiao
    2012, 0 (1): 77-82.  
    Abstract ( 757 ( PDF (2811KB)( 397 Citation
    On basis of reaction theory of urea and formaldehyde which were used as microcapsule shell materials, preparation technology of microcapsules containing αolefin drag reducing polymer was studied by using in situ polymerization method with urea and formaldehyde as shell materials. Preparation, storage stability and dissolving property of microcapsules were studied by using particle analyzer, FTIR, simultaneous thermal analyzer and simulation circular oil evaluation system of drag reducing rate and so on. The results show that, when microcapsules containing αolefin drag reducing polymer are prepared by in situ polymerization of urea and formaldehyde in acidic conditions, the preparation technology has properties that reaction implements in mild conditions, polycondensation is easily held and the reaction accomplishes quickly. The particle size distribution of microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material concentrates on 200μm. Microcapsules can keep condition of smooth small balls for long time and have excellent thermodynamic stability. The results of untistatic pressure storage stability and thermodynamic stability show that, microcapsules meet the qualifications of storage stability. Microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material have excellent dissolving property in oil. The drag reducing rates of microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material and uncoated αolefin drag reducing polymer particles are similar. Though there is some time delay in drag reducing rate to microcapsules contrasted with uncoated particles, the peak value of drag reducing rate is equivalent, and meets the standard of practical in situ engineering application.
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    Fe3Si Based Ordered Alloyed by Cr/Al and Their Degree of Ordering
    ZHOU Qi, JIA Jian-gang, ZANG Shu-jun, ZHAO Hong-shun, WU Hai-tao
    2012, 0 (1): 83-88.  
    Abstract ( 728 ( PDF (4069KB)( 303 Citation
    Based on the modification principle and adjustment of materials order degree,four kinds of Fe3Si based ordered alloys alloyed with Cr and Al were prepared by vacuum arc melting and annealing. Meanwhile, the alloys were characterized by XRD, SEM, EPMA,and the degree of ordering of the ordered phase was evaluated by the long range order (LRO) parameter.The result shows that four kinds of ordered intermetallics have different microstructure. With the decrease of Si content, the degree of order decreases. The effect of Al and Cr alloying plays a promoting roles in the decreasing tendency of degree of order. At the same content of Si, the order degree of Fe65Si25Cr5Al5 is lower than that of Fe3Si. The order degrees of Fe65Si25Cr5Al5 and Fe3Si are 0.658 and 0.796 respectively.
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    Preparation and Mechanism of γAlOOH with Special Structures by Solventthermal Approach
    WANG Guang-jian, LIU Xiao-na
    2012, 0 (1): 89-92.  
    Abstract ( 945 ( PDF (5263KB)( 322 Citation
    The white powder precursors were prepared at 200℃ with organic aluminum salt as materials, with ethanol as solvent, and with ammonia and urea as precipitator respectively. The samples were studied by SEM, XRD and BET techniques. The results show that nanorods and nanoflakes of γAlOOH are achieved by aluminum isopropoxide and aluminum acetate respectively. The specific surface area of product is affected by the type of solvent and precipitant, the highest being 218.64m2/g with urea as precipitator. The causes of formation were analyzed further from the crystallization mechanism.
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    Advance in Research of Casting Defects of Directionally Solidified Nickelbased Single Superalloys
    ZHAO Xin-bao, LIU Lin, YANG Chu-bin, ZHANG Jun, LI Yu-long, FU Heng-zhi
    2012, 0 (1): 93-98.  
    Abstract ( 1827 ( PDF (1111KB)( 1084 Citation
    Casting defects are deleterious to the mechanical properties of nickelbased single superalloys, the decrease of casting defects is benefit for improving mechanical properties and reducing the cost. Some important casting defects formed in the directional solidification process are discussed, including porosity, freckles, misorientation and stray grains. Based on the features and formation mechanisms for the defects, the influence of alloy composition, processing parameters and casting structure on the casting defects is analyzed. Meanwhile, the suggestions for reducing casting defects are pointed out.
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