HAO Li-mei. Research of Simulation Dendritic Growth of Polycrystalline Non-isothermal Binary Alloys by Phase Field Method[J]. Journal of Materials Engineering, 2010, 0(6): 1-6,11.
Numerical simulation based on phase field method is developed to describe polycrystalline solidification of the non-isothermal binary alloy,the evolution of the interface morphology is showed and the effect of anisotropy parameter is formulated for Ni-Cu alloy.The results indicate that,with increase in time,all of nuclei grow from independence to competition.The nuclei grows into an asymmetry dendritic with a forced flow,that is,upstream dendritic arm is promoted,downstream is inhibited and tilts to down direction,and perpendicular arms have no obvious change,but tilts to upstream direction.The asymmetry of dendritic shape is intensified as the forced flow velocity is increased,where there is a secondary dendritic in the upstream direction of perpendicular arms,while there is no secondary dendritic in the downstream direction.With increase in anisotropic values or undercooling values,the size of every dendritic increase.
YOU Rui-yun, XIAO Li-ren, LIU Xin-ping, LIN Cong-li, HUANG Bao-quan, XU Jing, CHEN Yu, CHEN Qing-hua. Rheological Properties of PE/CaO Composites[J]. Journal of Materials Engineering, 2010, 0(6): 7-11.
PE/CaO composites were prepared by blending polyethylene(PE) and calcium oxide(CaO).The rheological properties of PE/CaO composites were investigated by Melt Flow Rate Instrument and AR2000 Rotation Rheometer.The results indicated that the flow activation energy of PE/CaO composites first increased and then decreased with increasing CaO content.Under lower CaO content(mass fraction,the same below) ≤20%,the linear viscoelasticity of the composites were the same to that of PE,and the zero shearing viscosity(η0) of the composites largened within a small range.Under higher CaO content(≥25%),the time stability of the composites decreased and the zero shearing viscosity(η0) increased evidently.
LIU Ran, WANG Xing-juan, LÜ Qing, GAO Yong-liang, XUE Xiang-xin. Thermodynamic Research of BN-MgAlON Composite Powders from Boron-rich Slag[J]. Journal of Materials Engineering, 2010, 0(6): 12-15.
Based on thermodynamic analysis,BN-MgAlON composite powders were synthesized by carbothermal reduction and nitridation from boron-rich slag and carbon black as raw materials.Phase composition and microstructure of products were determined by X-ray diffraction(XRD),energy spectral analysis and scanning electron microscopy.The experimental result showed that B2O3 was transformed into BN,Al2O3 and SiO2 form MgAlON phase which could react with high purity nitrogen and holding time 8h at 1480℃.Reaction products were consisted of MgAlON,BN,CaAl4O7 and Sialon.The results demonstrate that full-fledged,octahedron crystallization can be prepared by the method of CRN.The technique provides a new strategy to comprehensive utilization of boron-rich slag.
WU Ya-di, CUI Sheng, HAN Gui-fang, SHEN Xiao-dong. Study on Preparation of Hydrophobic Silica Aerogels[J]. Journal of Materials Engineering, 2010, 0(6): 16-19,25.
Hydrophobic silica aerogels with 165° contact angle,from TEOS as silica source,have been prepared at supercritical drying by in situ method from MTES as modifier.The effect of ethanol,water,pH value on gelation time and density were investigated.The result showed that the optimal technics parameter was follows: TEOS:H2O:EtOH molar ratio 1:4:16,pH value 8.0.
ZHU Zhen-tao, WANG Pei-yan, WANG Fu-sheng, YUE Zhu-feng. Study of Experimental Investigation of Tensile Compress and In-plane Shear Properties Dispersibility of Composite Laminate[J]. Journal of Materials Engineering, 2010, 0(6): 20-25.
For fiber reinforced T300/QY8911 composite laminate,the tensile,compress and in-plane shear experiments were carried out to get main mechanical characters.The strength and rigidity characters of the fiber reinforced composites are studied and found that the stress-strain relations of tension compression and shear are almost linear,specimen’s failure is abrupt.The distribution properties of the mechanical characters are also studied with the method of statistical analysis.The result of the statistical analysis shows that 3-parameter weibull distribution,Normal distribution and lognormal distribution are good functions to describe the distribution properties of the mechanical characters.Finally,the parameters of the dispersibility of the tensile compress and shear properties of composite laminate are given.
XIONG Yi, XIONG Liang-yin, CHEN Zheng-ge, ZHANG Ling-feng, ZHOU He-yu, CAI Da-yong. Study on the Short-term Aging Behavior of GH199 Alloy[J]. Journal of Materials Engineering, 2010, 0(6): 26-29,35.
Short-term aging behavior of GH199 alloy was investigated at 650-1000℃ for 1-24h by using transmission electron microscopy(TEM) and ball hardness test.The results showed that the γ′phase was evolved gradually from ellipse to spherical shape to quadrate during aging treatment and the γ′phase size increased with the increase of aging time.The alloy hardness increased rapidly and then it was invariable gradually with the increase of aging time during the aging treatment at 700-800℃,but the alloy hardness increased rapidly and then it descended gradually with the increase of aging time during the aging treatment at 850-1000℃.The maximum of HB388 was obtained at 800℃,the time,which the peak value of the alloy hardness was reached,would be shortened from 8h to 2h with the increase of aging temperature.
QIAO Rui-hua, ZHAO Peng, ZHU Li-ran, PU Yu-ping. Effect of Pore Size on Permeability of Electrodeposited Copper Foam[J]. Journal of Materials Engineering, 2010, 0(6): 30-35.
Copper foams with same porosity but different pore sizes were prepared by electrodeposition method,pore structures were observed and pore sizes were calculated by Scanning Electronic Microscope(SEM),steady-state unidirectional pressure-drops to changing velocity of air flow were measured by PBR-1 permeability tester,permeability characters of the samples were determined.The results showed that in the experimental flow velocity range,the relationship between pressure-drops and flowing velocities followed Forchheimer equation,which means the flow state belong to transition state between static flow and turbulent flow.The permeability characters as the permeability K1,inertia coefficient K2 and form coefficient f for 5 types of copper foam was deduced,the effect of pore size d on the permeability characters were analyzed,the empirical equation between the pore size and permeability of electrodeposited copper foam in transition state between static flow and turbulent flow was set up.
LI Ping, HAO Jing-yan, ZHAO Jie, DUAN Hong-tao. Nondestructive Evaluation of Elastic Property of Titanium Alloy with Low Elastic Modulus[J]. Journal of Materials Engineering, 2010, 0(6): 36-39.
The ultrasonic velocities of Ti6Al4V and Ti27Nb8Zr aging samples were measured by longitudinal grazing incidence method,the elastic modulus were deduced and compared with those obtained by means of tensile method.It was found that these two methods showed comparable results,the changing range was only 3.6%,which indicated that it was feasible to evaluate the elastic property of titanium alloy with low elastic modulus by longitudinal grazing incidence method.It is valuable for the elastic evaluation of rare alloy with small dimension.Effect of aging temperature on the elastic modulus of Ti18Nb7Zr was observed by this method.The results showed that,with much higher aging temperature,elastic modulus E,shear modulus G and bulk modulus K increased 11%,10% and 6% respectively,whereas,Poisson’s ratio σ only decreased 1.2%.It is thought that the varied elastic modulus is closely related to the transformation from lamellar β +α phase to dispersed α phase and β phase.
XIONG Qing-ren, FENG Yao-rong, ZHANG Jian-xun, ZHAO Wen-zhen, LIU Chuan. Analysis for Factors Affecting Strength Testing of SAWH Pipe with Large Diameter[J]. Journal of Materials Engineering, 2010, 0(6): 40-44,49.
The several issues such as the type of specimen and the test procedure which affects the strength testing of SAWH pipe are analyzed.It is presented that the yield strength value of base metal in transverse direction of SAWH pipe from different kinds of specimen may be affected by many factors,such as Bauschinger effect,strain hardening effect,bending angle of the specimens and microstructure etc.The yield strength values were measured by two kinds of tensile specimen cut from SAWH pipe for the 2nd West-East Pipeline Project,the results show that Bauschinger effect is the main factor affected the yield strength measurement for the SAWH pipe used in the 2nd West-East Pipeline Project.It is suggested that the total elongation in total extension under load method for high grade SAWH pipe should be verified by ring expansion test.
HAN Li-hua, MA Qing-guo, FENG Xiao-jian, KANG Ju. Study of the Corrosion Resistance of KH-560 Silane Film on Hot-dip Galvanzied Steels[J]. Journal of Materials Engineering, 2010, 0(6): 45-49.
Orthogonal experiment was used to study the passivation process on galvanized steel with silane.A KH-560 silane passivating treatment process was studied on galvanized steel.The electrochemical behavior of KH-560 silane film on galvanized steel in 5% NaCl solution was evaluated by polarization curves and electrochemical impendence spectroscopy.And more by the NaCl immersion test validate the corrosion resistance of KH-560 silane film.Results showed that the corrosion current density decreases and the polarization resistance increases after KH-560 passivation.KH-560 silane film inhibits the corrosion rate of the galvanized steel.After KH-560 passivating treatment,the corrosion resistance of the conversion coating was better than that of without passive films,and almost as well as chromate coatings.
PIAO Zhong-yu, XU Bin-shi, WANG Hai-dou, PU Chun-huan. Experimental Investigation of Fatigue Wear Life of Fe-based Coating Under Rolling Contact[J]. Journal of Materials Engineering, 2010, 0(6): 50-53,58.
Fe-based alloy coatings were deposited on the AISI1045 steel by using supersonic plasma spraying device.A ball-on-disc fatigue wear tester was employed to evaluate the fatigue wear performance of Fe-based coating under two types of loading conditions.Two-parameter Weibull distribution was introduced to characterize the fatigue lives.The Scanning Electron Microscopy(SEM) was used to analyze the coating microstructure and worn surface.The Finite Element Method(FEM) was employed to investigate the stress distribution within the coating.Results showed that loading condition play an important role on the fatigue wear lives and failure modes of coatings,the life obviously decreased under high load.The key failure mode charged from abrasion failure to delamination failure,as the load increased.The abrasion failure was associated with asperity contact,whereas the delamination failure had much to do with the stress distribution within the coating.
MA Feng, WANG Xiao-yan, LI Fei, CHEN Ming-hui. Preparation and Thermal Performance of Shape-stabilized Energy Storage Phase Change Building Materials[J]. Journal of Materials Engineering, 2010, 0(6): 54-58.
A shape-stabilized composite phase change building material(PA-HD/EP) for latent heat storage was prepared by vacuum infiltration method using the eutectic mixture of palmitic acid(PA) and hexadecanol(HD) as phase change material,expanded perlite(EP) as skeleton.Environmental scanning electron microscope showed that PA-HD had entirely penetrated into pore structure of the matrix material.The optimum PA-HD Absorption of EP was found to be 58%(mass fraction,the same below) without melted PA-HE leakage from the PA-HD/EP composite.By differential scanning calorimetry thermal analysis,the phase change temperature and the phase transition enthalpy of melting for PA-HE/EP composite were found to be 41.49℃ and 122.9J/g respectively.The thermal conductivity of the PA-HD/EP composite was obviously increased by adding 10% graphite.The composite can integrate with normal building materials well,so that the building material which has thermal adjustment function can be prepared further.
GU Xiao-yan, SUN Da-qian, LIU Li, DUAN Zhen-zhen. Microstructural Evolution of TLP Bonded Ti3Al Based Alloy/Ti-6Al-4V Joint[J]. Journal of Materials Engineering, 2010, 0(6): 59-62,67.
Composition,microstructural evolution and micro-hardness of TLP bonded Ti3Al based alloy/Ti-6Al-4V joints have been studied using a TiZrNiCu alloy as interlayer.Experimental results showed that bonding temperature and bonding time have a great effect on joint composition and microstructure.With increasing bonding temperature and bonding time,composition distribution of joint had a uniform tendency and width of the bond zone increased.When bonding temperature were 850℃ and 900℃,Ti-Cu intermetallics were found in the joint due to the existence of residual liquid.When bonding temperature was 950℃ and bonding time was 30min,Ti-Cu intermetallics disappeared from the joint owing to completion of isothermal solidification.Micro-hardness of bond zone decreased as bonding temperature and bonding time were increased.When bonding temperature was 950℃ and bonding time was 30min,the joint acquired a relatively uniform micro-hardness distribution.
LIU Jing-fu, LI Rong-de, XIE Yi, WU De-feng. Research on Processing and Microstructure of Spray Forming ZA35 Alloy with High Mn Amount[J]. Journal of Materials Engineering, 2010, 0(6): 63-67.
The ZA35 alloy with 3.5%(mass fraction,the same below) Mn is manufactured with spray forming technique using the optimized parameters.The microstructure of the alloy(casting,spray forming) are observed.It is indicated that the microstructures of spray formed high Mn ZA35 alloy distribute homogeneous and the grains are refined.The element Mn exists mainly in the form of Mn-enriched independent hard phase in or near the interfaces of grains of casting ZA35 alloy,but the Mn-enriched independent hard phases are not found in spray formed high Mn ZA35 alloy.The solid solubility of Mn in ZA35 matrix is shifted considerably to a higher level by spray forming.The distribution of element Mn in casting and spray forming ZA35 matrix is uniform,the solid solubility in α phase is higher than in η phase.The nano whisker and particle of MnAl6 is obtained in spray formed high Mn ZA35 alloy after heat squeezing.
LIANG Fang-hui, LI Tong, CHEN Bo, MAO Wei, HUANG Yong-ling, ZHOU Xue-yu. Investigation of Porous Pure Titanium/Titanium Alloy Coating Brazed on Titanium Alloy Surface[J]. Journal of Materials Engineering, 2010, 0(6): 68-72.
To obtain titanium alloy implant with porous coatings,porous pure titanium/titanium alloy coatings brazed on titanium alloy were investigated.Brazing filler metals contain no elements with potential toxicity such as Cu,Ni.The results indicated that after brazing at 950℃ for 30 minutes,the pore size of the coating made of pure titanium of titanium alloy powders with size more than φ0.2mm was greater than 100μm,and the porosity was about 6.0%-8.8%.Bonding-strengths between substrates and porous coating were greater than 20MPa.Pore size,porosity and bonding strength could meet the demand of implant.The microstructure and the tensile strength of the substrates was influenced scarcely by the brazing thermal process and were coincidental with those requirements in the standard YY 0117.1.The result of biomedical evaluation indicated that porous coating had excellent biocompatibility.
LIU Wen-hui, GUO Shao-qing, YE Lei, MAO Wei, ZHOU Biao. Microstructure and Property of the GH783 Joint Brazed with BNi68CrWB Filler Metal[J]. Journal of Materials Engineering, 2010, 0(6): 73-77,83.
The vacuum brazing test of GH783 was carried out by using BNi68CrWB filler.Microstructure and property of the brazed GH783 joint were investigated.The tensile strength of the joint was quite high under the heating condition of 1180℃/10min.All of the brazed joints were subjected to heat treatment.The maximum joint tensile strength at room temperature reaches 701MPa,and at 650℃ the maximum joint tensile strength reaches 696MPa.Microstructure of the brazed joint consists of nickel-cobalt based γ solution,eutectic and other brittle phases.The ratio of the solution in the joint was different when the joint clearance was changed.Elements in the joint with 0.05mm joint clearance diffuse more adequately,resulting in a lower content of eutectic and other brittle phases and higher content of solution.The joint clearance has an influence on the joint strength.Compared with 0.1mm joint clearance,the tensile strength of the joint with 0.05mm joint clearance is remarkably higher.
ZHAI Hua-zhang, LI Jian-bao, WU Jiang, CAI Hong-nian. Applications and Performance Testing of High-temperature Ceramics for Heat Engine Components[J]. Journal of Materials Engineering, 2010, 0(6): 78-83.
Research and development on ceramic engines were reviewed.The improvements on the properties of silicon nitride ceramics and mullite coating for heat-engine parts and the performance testing in the high-temperature engine environments were introduced in details.
WU Kai-ming, ZHOU Zhen-ni, ZHANG Guo-hong, ZHANG Jing-jing. Effect of High Magnetic Field on the Decomposition of Austenite in Fe-based Alloys[J]. Journal of Materials Engineering, 2010, 0(6): 84-89.
The development and application of high magnetic field in metallic materials research are precisely presented.The basic principles of influence of high magnetic field on the decomposition of austenite are described.Effects of high magnetic field on martensitic,bainitic,pearlitic and ferritic transformation temperatures,transformation behavior and transformed structures in Fe-based alloys are briefly reviewed.The start transformation temperatures are increased and the transformation behavior is accelerated by applying high magnetic fields.Being a new approach,high magnetic field plays an important role in the control of structures and properties of materials.Quantitative control of transformation and precipitation by applying high magnetic fields remains to be further investigated.
ZHANG Lin, QU Xuan-hui, HE Xin-bo, DUAN Bai-hua, QIN Ming-li. Research Progress of ODS Nickel Based Superalloy[J]. Journal of Materials Engineering, 2010, 0(6): 90-96.
Oxide Dispersion Strengthening(ODS) nickel-base superalloy strengthened by γ′ and oxide dispersion exhibits excellent creep resistance above 1000℃,which can be used as turbine blade material in advance jet engine.The fabrication process and three-step heat treatment to obtain coarse elongated grain were introduced.The main focus was on the special recrystallization behaviour and the effects of preannealing were analyzed,the moving speed of hot zone and the content of γ′ and Y2O3 on secondary rescystallization were analyzed.Three kinds of theories including secondary rescystallization induced by the dissolution of γ′ or the coarsening of dispersion and the grain boundary nucleation theory were discussed.The high rescystallization temperature and high activation energy was explained.Finally,the mechanical properties of the material with fine grain and coarse elongated grain,as well as the effects of orientation and strain rate were analyzed.
