WANG Xiao-qiang, ZHU Xi, MEI Zhi-yuan, LI Wei. Experimental Investigation into Anti-penetrating Capacity of Low Alloy Ship Hull Steel Structures to High Velocity Steel Fargment[J]. Journal of Materials Engineering, 2009, 0(8): 1-5.
The capacity of anti-penetrating of low alloy ship hull steel structures with different thicknesses was investigated by ballistic experiment.The projectiles' residual velocities and the targets' absorbing energy were gained.The relations of unit area absorbing energy,residual velocity,initial velocity and thickness were established.Based on the relations,the values of residual velocities and unit area absorbing energy were predicted.The predicting results were approximately coincident with the experimental conclusions.
LIN Xin-zhi, MA Xu-liang. Effect of B Addition on Microstructure and Abrasive Property of TiC/Ti6Al4V Composites[J]. Journal of Materials Engineering, 2009, 0(8): 6-9.
In-situ titanium alloy matrix composites were fabricated by melting-casting method and the effect of B content on microstructure and abrasive property of TiC/Ti6Al4V composites was studied.The results show that the average grain size of dendritic TiC in the composites is remarkably refined when the addition content of B is less than 0.06%(mass fraction).TiC dendrite gradually changes into small dendrite or even granular from coarse dendrite,but the abrasive property is obviously reduces with the increasing of B content.When B content further increases form 0.1% to 0.6%,the dendritic TiC can not be refined obviously,the fibre-shape TiB appears and the abrasive property of composites is improved.The refinement mechanism of boron is attributed to the combined effects of the increasing in nucleation rate at the constitutional supercooling zone ahead of the solidification front and the reduction in growth rate.The improvement of its abrasive property is attributed to the present of fibre-shape TiB during the abrasiving.
ZHOU Zhen-ni, ZHANG Jing-jing, WU Kai-ming. Effect of High Magnetic Field on Ferrite Transformation in Fe-0.28%C-3.0%Mo Alloy[J]. Journal of Materials Engineering, 2009, 0(8): 10-14.
The transformation of degenerate ferrite in an Fe-0.28%C-3.0%Mo alloy was investigated by isothermal holding under a 12T magnetic field.The degenerate ferrite was observed around and below the bay temperature with and without the magnetic field.The results show that the degenerate ferrite transformation is accelerated by applying a 12T magnetic field.The bay temperature of TTT-curves is raised in magnetic field,i.e.The bay temperature is about 610℃ without a magnetic field whereas it becomes approximately 640℃ with a 12T magnetic field;because the free energy of degenerate ferrite is lowered by a high magnetic field.
BI Feng-qin, ZHANG Xu-yun, WANG Yong, SUN Li-li, WANG Yang. Research on Stress Corrosion Behavior of X70 Pipeline Steel in H2S Environment[J]. Journal of Materials Engineering, 2009, 0(8): 15-18,23.
Based on the uniformity design method,the slow strain rate testing(SSRT) of X70 pipeline steel in different concentration of H2S,concentration of Cl-,pH value and temperature was tested.After analysing the microcosmic morphology by SEM,judging the nature of stress corrosion sensitivity and calculated the stress corrosion sensitivity index in different examination environments.Based on the analysis by the regression analysis software,the relations between the intercross mathematics model of stress corrosion sensitivity index of X70 pipeline steel and the medium parameters(concentration of H2S,concentration of Cl-,pH and temperature) were established.
DONG Li-hong, XU Bin-shi, DONG Shi-yun, SONG Li, CHEN Qun-zhi, SHI Chang-liang. Discussion on Characterizing Stress Concentration,Residual Stress and Defect by Metal Magnetic Memory Testing[J]. Journal of Materials Engineering, 2009, 0(8): 19-23.
The relationship between stress concentration,residual stress and defect was discussed.Some cases were presented to analyze the response of metal magnetic memory signals to the different degree of stress concentration,fatigue crack and residual stress.The results show that metal magnetic memory testing is suitable to detect the positions with rapid change of magnetic permeability.Further investigation is needed to determine whether metal magnetic memory signals can characterize residual stress.
HE Ding-yong, WANG Xiao-fang, CUI Li, JIANG Jian-min, LI Xiao-yan. Investigation of Chromium Content on Elevated Oxidation Resistance of Iron-based Coating[J]. Journal of Materials Engineering, 2009, 0(8): 24-27.
Four kinds of high temperature oxidation resistant iron-based coatings were prepared by arc spraying process.Oxidation experiments of these coatings were carried out at 800℃ in air for up to 240h.The morphologies,composition,and phase structures of the oxidation products were investigated using scanning electron microscopy(SEM) and X-ray diffraction analysis(XRD).The results show that the Cr content plays an important role in the oxidation resistance.When the Cr content contained in the coating is more than 40%(mass fraction),a continuous Cr2O3 passivation layer is developed on the surface of the coating,leading to good high temperature oxidation resistance.In the low Cr-containing coating,e.g.,lower than 30%,only a small quantity of spinel structured FeCr2O4 was formed on the surface of the coating,which provides protection to the substrate.However,most of the oxidation products are loose structured Fe2O3,and are easy to spall off,resulting in a poor effect in substrate protection.
ZHU Shi-dong, BAI Zhen-quan, YIN Cheng-xian, LIN Guan-fa, YIN Zhi-fu. Behavior Investigate of Counter Erosion-corrosion of P110 Steel[J]. Journal of Materials Engineering, 2009, 0(8): 28-32.
Influences of several factors on CO2 corrosion behaviors of annulus P110 steel were investigated in stimulated oil and gas field environments.The corrosion scales were analyzed by using scanning electron microscope(SEM),energy dispersive X-ray spectrometer(EDS) and X-ray diffractometers(XRD).Simultaneously,the corrosion rate was measured by the mass loss method.The counter erosion-corrosion mechanism of P110 steel was researched after analyzing the influences of several factors on CO2 corrosion behaviors in dynamic state.
LIU Chang-kui, TAO Chun-hu, CHEN Xing, ZHANG Bin, DONG Shi-yun. Research on Quantitative Assessment of Fatigue Damage by Metal Magnetic Memory Methods[J]. Journal of Materials Engineering, 2009, 0(8): 33-37.
Fatigue tests of notched 18CrNi4A steel specimens were carried out under three different fatigue stresses and metal magnetic memory(MMM) signals were detected.The variation of the MMM signals and the quantitative assessment of fatigue damage by MMM methods were investigated.The results show that the variation of the MMM signals is unobvious before the cracks initiate,but the MMM signals increase obviously with the propagation of the cracks and vary abruptly after rupture.There is an inherent relationship between the fatigue stress and the feature parameters Kmax,Hp(y)max,Hp(y)min and Hp(y)sub,the larger the fatigue stress or fatigue damage is,the larger the absolute values of the feature parameters are.The fatigue damage can be assessed effectively by obtaining the average value of Kmax.The basis of this method is that if the value of m(m=Kmax/KmaxAV) is larger than 1,there will be serious fatigue damage.
LIU Bin, TAI Feng, GUO Fu, XIA Zhi-dong, SHI Yao-wu. Research of New Sn-Ag Based Lead-free Composite Solders Containing Nano-structured Reinforcements[J]. Journal of Materials Engineering, 2009, 0(8): 38-42,48.
Composite solders were fabricated by mechanically mixing the Sn-3.5Ag solder paste with nano-scale of 1%(mass fraction),2% and 3% polyhedral oligomeric silsesquioxanes(POSS) particles.POSS microstructure,melting characteristic,wetting property and shear strength were investigated.The results showed that the POSS particle didn't change the melting temperature of composite solders.Addition of POSS in the Sn-3.5Ag solder increased the spreading area and decreased the contact angle of lead-free composite solder.Shear strength of POSS particle reinforced composite solder joints were improved remarkably.
YIN Chang-ping, XIAO Jia-yu, ZENG Jing-cheng, JIANG Da-zhi, LIU Jun, DAI Xiao-qing. Heat Transfer Analysis of Integral Composites Fabricated by Co-injection RTM[J]. Journal of Materials Engineering, 2009, 0(8): 43-48.
On the basis of the structure of loading-bearing/heat-insulated/thermal protective integration material,which loading-bearing layer material was carbon fiber reinforced epoxy resin,heat-insulated layer material was foam,and thermal-protective layer material was carbon fiber reinforced phenolic resin,the finite element analysis(FEA) model was built to analyze the heat transfer of the integral composite materials.The temperature distribution inside the integral material was calculated by using the model,and the effects of thickness of thermal-protective layer,thickness and thermal conductivity of heat-insulated layer on temperature field were discussed.Silica aerogel composite was consumed to substituted the foam to fabricated the heat-insulated layer,the thickness satisfied the defined thermal environment condition was calculated,the results were important for heat transfer design of the integral material using silica aerogel composite as heat-insulated layer.
XU Ying, WANG Wei, WANG Juan. Preparation of Nanometer Fe from Blast Furnace Wet Dust by Two-step Method[J]. Journal of Materials Engineering, 2009, 0(8): 49-52.
Blast furnace wet dust was taken as raw material,and nanometer Fe was prepared by two-step method.The variation regularity of the matter was to be focused on,so was the relationship between microcosmic structure and performance characterization.The final product was inspected by X radial diffract,scan electron microscope,X radial photoelectron spectrum and vibrancy sample magnetism.The results show that the powder is nanometer α-Fe,its average size is 74nm.There is oxide of Ni enwrapped on the surface of Fe particles.The saturation magnetization intensity Ms of nanometer Fe is 60.85 A·m2·kg-1,and the remaining magnetization intensity Mr is 12.226A·m2·kg-1,while the coercive force Hc is 21.41kA·m-1.
SONG Zi-biao, LIU Dai-zhi, WANG Hong-xia. Experimental Studies on Aerodynamics Properties of Carbon Nanomaterials[J]. Journal of Materials Engineering, 2009, 0(8): 53-56,62.
The mass concentrations and transmissivity to 1.06μm laser emission of eight kinds of carbon nanomaterials smoke screens sprayed in the smoke box were measured,and the deposition velocities of smoke screens were computed according to the mass concentrations at different time.The results show that the carbon nanomaterials smoke screens have excellent suspending characteristics and the dispersing of carbon nanomaterials has a great effect on mass concentrations and deposition velocities of smoke screens.Considering mass concentration and deposition velocity,the carbon nanofibers with diameter over 40nm and length less than 15μm are more appropriate for electromagnetic-wave passive interference materials.As dispersant,nano-SiO2 can effectively increase the fluidity and dispersibility of carbon nanomaterials,and it can evidently prolong the suspending time and decrease the deposition velocities of smoke screens.
WEI Shi-tong, LU Shan-ping, LI Dian-zhong, LI Yi-yi. Temperature Variation Simulation of Controlled Cooling Heavy Plate and Analysis of Its Microstructures and Mechanical Properties After Cooling[J]. Journal of Materials Engineering, 2009, 0(8): 57-62.
A numerical model was developed and applied to a specific runout table to predict the temperature variation in a heavy plate cooled by an array of laminar flow water bars.Radiation,natural convection,forced convection and stable film boiling are considered in the model.The model is validated by comparing the predicted temperatures with the measurements obtained on the runout table of a steel mill.In addition,the microstructures and mechanical properties at different locations through the thickness of the heavy plate are investigated systematically.
GONG Kai, HUANG Yin-hui, TIAN Zong-jun, LIU Zhi-dong, Wang Gui-feng. Research on Technological Process of Bulk Porous Nickel Prepared by Scanning Jet Electrodeposits[J]. Journal of Materials Engineering, 2009, 0(8): 63-67.
The bulk porous nickel sample was introduced and made by jet scanning electrodeposition forming.The surface morphology,microstructure,grain size of the micro-cell structure of deposition,were studied and analyzed by means of SEM,and the mechanical properties of the sample were also studied,such as surface micro-hardness and compressive property.The results show that,using jet scanning electrodeposition in current density of 900A/dm2,the prepared sample's porosity is 61.5%.The surface micro-hardness of the sample reaches to HV 330.5.The compressive yield stress of porous nickel is 11.85MPa,which has a large number of plastic deformations of the absorption capacity.
ZHANG Hua-xia, WU Chang-xin, GUI Zhong-lou. Study on Purified DZ125 Superalloy Revert[J]. Journal of Materials Engineering, 2009, 0(8): 68-70,75.
A purification technology of the nickel-base DZ125 alloy revert was studied in the industrialized vacuum induction furnace.Inclusions quantity was tested by electron beam buttons.Purification effect,compositions,mechanical property and castabilitiy of purified revert and normal green alloy was studied.The results show that the quantity of inclusions of the revert was significantly decreased.Quantities of inclusions of purified 100%revert is slightly lower than one of the normal 100% green,and rupture life slightly higher.It also shows the same effect at composition,room temperature tensile properties and castabilitiy.
LI Jing-yuan, CHEN Yu-lai, CHEN Chang-jiang, CAO Liang. Effect Factors of Extrusion Deforming of High Al Content Magnesium Alloy[J]. Journal of Materials Engineering, 2009, 0(8): 71-75.
Based on the composition standards of AZ91-D magnesium alloy,four kinds of Mg-Al-Zn high strength magnesium alloys with various Al,Zn and Mn contents were designed.Hot extrusion with different dies and pre-treatment were carried out on 650t extruder.The results show that Al and Zn alloy elements have a great impact on the extrusion deforming,but the effect of Mn has not been observed.Homogenization pre-treatment can raise the plasticity of materials in a certain degree.Streamlined dies can make the material to flow better than flat dies and conical dies.After extrusion,the strength and plasticity of the employed alloys are greatly improved.The grain is refined to average diameter of 20μm,the tensile strength reaches 340MPa,and the elongation is beyond 12%.
JIANG Hai, LI Dong-sheng, WU Feng-qiu, DENG Hai-jin. Study on Composition and Processing of C/C Composite Brake Disc with Random Fiber Preform[J]. Journal of Materials Engineering, 2009, 0(8): 76-79.
The manufacture process of random fiber perform was developed via studying the pressing point temperature and pressing pressure at short-fiber prepreg moulding process.The results show that pressing point temperature at 130℃ and 10MPa pressing pressure for the preform fitting MD-90 aircraft C/C composite brake discs is the best choice.The preforms of different composition were densified by atmosphere CVD process up to 1.65g/cm3.The results show that the preforms with the composition of no-twisted T700-12K carbon fiber,35%(mass fraction) resin content and 40mm length has best mechanical performance.
YU Juan, JIANG Yuan-yuan, WANG Xiao-dong, HUANG Pei. Effect of High Temperature Treatment on Properties of Sol Film for Polyimide Precursor[J]. Journal of Materials Engineering, 2009, 0(8): 80-83.
The thermal stability and mechanical properties of sol film for polyimide precursor with different temperature treatment,and the effect of heating rate on degree of imidization was investigated.The results showed that the imidization degree of films decreased slightly with increase of heating rate,but the thermal stability and mechanical property obviously improved with increase of temperature,the tensile strength and elastic modulus increased to 107MPa and 2770MPa respectively.
CAI Jian-ming, MA Ji-min, HUANG Xu, CAO Chun-xiao. Diffusion Behavior of Impurity Iron in High Temperature Titanium Alloys and Its Detrimental Effect on Creep Resistance[J]. Journal of Materials Engineering, 2009, 0(8): 84-88.
High temperature titanium alloys were idea materials for advanced aero-engine compressor use due to their excellent contribution to the spectacular progress in thrust-to-mass ratio and operating performances,which had been achieved through the substitution of titanium alloys for steel or Ni-based superalloys.With increasing the operating temperature of titanium alloys,creep resistance becomes the most important mechanical property which may affect the operating temperature and service lifetime.Over the temperature range from 400℃ to 600℃,creep deformation of titanium alloys is primarily controlled by dislocation climb mechanism,the activation energy of creep is close to the activation energy of effective diffusion.Therefore,diffusion plays an important role in dominating creep resistance for high temperature titanium alloys.The impurity iron has an abnormal high diffusion ability which is 103-105 times as large as that of self-diffusion in titanium,and may be attributed to the dissociative diffusion mechanism.Meanwhile,trace iron may promote the self-diffusion of Ti,thus may increase the dislocation climb rate and reduce the creep resistance.In order to improve the creep resistance of high temperature titanium alloys,the content of impurity iron must be carefully restricted in the raw materials such as titanium sponge and master alloys.
