GUO Qi-wen, CAI Hong-nian, WANG Fu-chi, ZHANG Hong-mei, YANG Chun, CHENG Jian. Comprehensive Application of Material Database System in Material Selection Evaluation[J]. Journal of Materials Engineering, 2012, 0(1): 1-4.
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.
LIU Shu-qian, HUANG Wei-gang. Microstructure and Mechanical Performance of AlCoCrNiSix Highentropy Alloys[J]. Journal of Materials Engineering, 2012, 0(1): 5-8.
The effects of Si contents on the variation of phase structure, microstructure characteristic and mechanical properties of AlCoCrNiSix highentropy 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 ascast 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 ascast microstructure. The Si element plays an important role in the increasing hardness of the AlCoCrNiSix alloy significantly, the highest microhardness is up to HV991.
REN Ming-xing, LI Bang-sheng. Phase Analysis of CrFeCoNiCu High Entropy Alloy[J]. Journal of Materials Engineering, 2012, 0(1): 9-12.
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 highentropy alloy is formed.
FENG Zhong-xue, PAN Fu-sheng, ZHANG Xi-yan, TANG Ai-tao, FU Qi-tao. Distribution Characteristics of Mg17Al12 in Semicontinuously Cast AZ61[J]. Journal of Materials Engineering, 2012, 0(1): 13-17.
Quantitative characteristics of the average size and the area fraction of Mg17Al12 phase were investigated in the center and the edge of the semicontinuously 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 backdiffusion in the solid has an effect on the area fraction of Mg17Al12 in the center of the ingot.
ZHAN Mei-yan, LI Chun-ming, ZHANG Wei-wen, ZHANG Da-tong. Interface Bonding of AZ31 Magnesium Alloys During Accumulative Rollbonding[J]. Journal of Materials Engineering, 2012, 0(1): 18-24.
Interface bonding mechanism of AZ31 magnesium alloys during accumulative rollbonding (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 microcracks. 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.
WANG Ying, YU Hong-ying, CHENG Yuan, SHAN Hai-tao, SUN Dong-bai. Corrosion Behavior of X80 Steel in Different Simulated Soil Solution[J]. Journal of Materials Engineering, 2012, 0(1): 25-28.
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 Xray 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 saltcrystallization 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.
LI Gui-hua, ZOU Yong, ZOU Zeng-da, WEI Xi-wang, TIAN Bao-lin. Insitu Synthesized Nb2(C,N) and V8C7 Ceramics Particulates Reinforced Febased Composite Coating by Laser Cladding[J]. Journal of Materials Engineering, 2012, 0(1): 29-33.
Febased composite coating reinforced by insitu 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 αFe，γFe phase，Nb2(C,N) and V8C7. Reinforcing ceramics particulates with granuliferous morphology are uniformly distributed in the Febase 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.
ZHANG Dong-qing, GUO Quan-gui, SONG Yan, ZHAI Geng-tai, LIU Lang. Effects of Hollowness on Properties of Hollow Phenolic Fibers[J]. Journal of Materials Engineering, 2012, 0(1): 34-37.
Hollow phenolic fibers with different hollowness were prepared by controlling thickness of the partiallycrosslinking spun filament derived from meltspinning 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, TGDSC 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.
LIU Bin, DONG Shi-yun, XU Bin-shi, HE Peng. Nondestructive Evaluation for Thickness of Laser Cladding Coating Based on Surface Acoustic Wave[J]. Journal of Materials Engineering, 2012, 0(1): 38-41.
In order to settle the problem for measuring the thickness of laser cladding coating by nondestructive method, the surface acoustic wave was used according to the properties of surface acoustic wave in material. The crosscorrelation 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 crosscorrelation 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.
YU Mei, DONG Yu, WANG Rui-yang, QI Jin-yu, LIU Jian-hua, LI Song-mei. Corrosion Behavior of Ultrahigh Strength Steel 23Co14Ni12Cr3Mo in Simulated Seawater Environment[J]. Journal of Materials Engineering, 2012, 0(1): 42-50.
The corrosion behavior of ultrahigh 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 Xray diffraction. The results show that the corrosion product layer is composed of outer rust layer γFeOOH and inner rust layer αFeOOH. 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.
YANG Kun, MEI Zhi-yuan, LI Hua-dong. Experimental Study on Creep Characteristics of Sandwich PUEPM Core Under Static Pressure of Deep Water Environment[J]. Journal of Materials Engineering, 2012, 0(1): 51-54.
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 quasistatic compression and bushing compression creep tests for three different microspheresreinforced polyurethanemodified 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.
LEI Yu-cheng, LIU Zhen-zhen, XUE Hou-lu, HU Wen-xiang, CHEN Xi-zhang, YAN Jiu-chun. Microstructure Features of Insitu SiCp/6061Al in Plasma Arc Welding by New Reinforced Phase[J]. Journal of Materials Engineering, 2012, 0(1): 55-58.
The aluminum matrix composite which reinforced by SiCp particles was added Al5Ti5Si as filling material in plasma arc “insitu” welding, and the alternating arcultrasonic 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 entirecoherent 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 lowdislocation 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.
NIE Xiang-hui, LI Xiao-gang, LI Yun-long, LI Ji-ke, ZHANG Hong-bo. Simulative and Accelerative Experimentation of Carbon Steel Corrosion in Soil[J]. Journal of Materials Engineering, 2012, 0(1): 59-65.
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 seashore 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.
LIANG Hao, CHEN Yong-mei, HU Wen-jun, FENG Jie, TAN Yun. Tensile Property and Fracture Surface for MgAlZnY Alloys at Different Strain Rates[J]. Journal of Materials Engineering, 2012, 0(1): 66-70.
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 0001, 01, 06s-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.
CHEN Yuan-qing, DENG Yun-lai, WAN Li, JIN Kun, XIAO Zheng-bin. Microstructures and Properties of 7050 Aluminum Alloy Sheet During Creep Aging[J]. Journal of Materials Engineering, 2012, 0(1): 71-76.
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.
LI Bing, YU Ping, DAI Xiao-dong, XING Wen-guo, DONG Gui-lin, ZHOU Ning-ning, QIN Zhan-bo, ZHANG Chang-qiao. Preparation and Properties of Microcapsules Containing αolefin Drag Reducing Polymer with Poly (Ureaformaldehyde) as Shell Material[J]. Journal of Materials Engineering, 2012, 0(1): 77-82.
On basis of reaction theory of urea and formaldehyde which were used as microcapsule shell materials, preparation technology of microcapsules containing αolefin 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, FTIR, simultaneous thermal analyzer and simulation circular oil evaluation system of drag reducing rate and so on. The results show that, when microcapsules containing αolefin 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 αolefin drag reducing polymer with poly (ureaformaldehyde) 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 untistatic pressure storage stability and thermodynamic stability show that, microcapsules meet the qualifications of storage stability. Microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material have excellent dissolving property in oil. The drag reducing rates of microcapsules containing αolefin drag reducing polymer with poly (ureaformaldehyde) as shell material and uncoated αolefin 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.
ZHOU Qi, JIA Jian-gang, ZANG Shu-jun, ZHAO Hong-shun, WU Hai-tao. Fe3Si Based Ordered Alloyed by Cr/Al and Their Degree of Ordering[J]. Journal of Materials Engineering, 2012, 0(1): 83-88.
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.
WANG Guang-jian, LIU Xiao-na. Preparation and Mechanism of γAlOOH with Special Structures by Solventthermal Approach[J]. Journal of Materials Engineering, 2012, 0(1): 89-92.
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 nanorods and nanoflakes of γAlOOH 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.
ZHAO Xin-bao, LIU Lin, YANG Chu-bin, ZHANG Jun, LI Yu-long, FU Heng-zhi. Advance in Research of Casting Defects of Directionally Solidified Nickelbased Single Superalloys[J]. Journal of Materials Engineering, 2012, 0(1): 93-98.
Casting defects are deleterious to the mechanical properties of nickelbased 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.
