ZHANG Wen-long, GU Ming-yuan, WANG De-zun, YAO Zhong-ka. Influence of Deformation Temperature on Matrix Metal Flow and Whisker Re-orientation in SiCW/6061Al Composites During Compressive Deformation[J]. Journal of Materials Engineering, 2002, 0(11): 3-6.
The matrix metal flow and whisker re-orientation in directionally aligned SiCW/6061Al composites during compressive deformation were investigated by observing the changes in the whisker orientation and specimen shape before and after compression.The results indicate that the matrix metal flow and whisker re-orientation during compressive deformation is dependent on deformation temperatures because of the directional alignment of whiskers in the composite At the higher temperature, the matrix metal can more uniformly flow and it is dependent on plastic strain fields for the ring and solid cylinder during deformation that whether the whiskers can re-orient during compressive deformation or not At the lower temperature,the whiskers in the composites can not re-orient during the compressive deformation.
YUAN Wei-dong, SHAO Tian-min, SE Dao, CHEN Da-rong. Preparation of AlCuFe QC Coatings by Plasma Spray and Laser Re-melting[J]. Journal of Materials Engineering, 2002, 0(11): 7-10,13.
This paper reported the study on laser re-melting of plasma sprayed AlCuFe quasicrystal-line coatings The results show that with the laser power fixed at 300W, increasing the laser scanning speed, the melting depth decreases resulting in the decreasing of the dilution rate of the substrate material Fe, results in the ratio of icosahedral phase to its approximant β phase to increase.When the laser scanning speed is above a certain value,the bottom of melting pool can not reach the interface of the coating and the substrate,the bonding strength is not improved.
ZHOU Xiao-yan, LI Qiang, SONG Feng-bing, ZHONG Zhi-feng. Preparation of Ce-substituted Yttrium Iron Garnets (Ce:YIG)[J]. Journal of Materials Engineering, 2002, 0(11): 11-13.
The substitution of Ce3+for Y3+was reported to extremely enhance magneto-optical(MO)properties of YIG In this paper, Ce:YIG were prepared via coprecipitation.The structure, physiognomy and state of Ceions were investigated respectively X-ray powder diffraction(XRD)analysis showes that Ce:YIG are pure cubic YIG Phase Scanning electron microscope(SEM)testing demonstrates the conglobation of Ce:YIG particles with the size of smaller than 0.5μm The results of X-ray photoelectron spectrum(XPS)demonstrate that the Ceions in Ce:YIG are in the state of trivalence.
TONG Qiao-ying, CHENG Lai-fei, ZHANG Li-tong. Microstructure and Properties of Joints of 2D C/SiC Composites[J]. Journal of Materials Engineering, 2002, 0(11): 14-16,21.
Liquid infiltration joining of carbon fiber reinforced silicon carbide(C/SiC)composites was carried out with Ni-base adhesive as the interlayer at the temperature of 1300℃ with various holding time in vacuum.The pressure applied in all the experiments was 20 MPa.Result shows that the Ni-base adhesive employed have favorable wettability with C/SiC composites through scanning electron microscopy(SEM)and energy-dispersive spectroscopy(EDS)Ni-base adhesive can infiltrate into the pores of the composites.The maximum three-point bending strength of joints shows the value of 60 MPa.
WANG Hui, REN Zhong-ming, LI Xi, GAO Yun, JIN Fang-wei, DENG Kang, XU Kuang-di. The Behavior of the MnBi Phase in Bi-Mn Alloy Aligned Along a Magnetic Field[J]. Journal of Materials Engineering, 2002, 0(11): 17-21.
The critical conditions needed to form MnBi regular structure have been studied experimentally in this paper during the solidification started from mushy zone of Bi-Mn alloys with a magnetic field It is found that the formation of MnBi regular structure in Bi-Mn alloy could be achieved rapidly in a magnetic field.The critical holding temperature in 6%Mn alloy is increased with the decrease of the applied magnetic field.The critical magnetic intensity need to form MnBi alignment structure in 6%Mn alloy was higher than that in 3%Mn alloy at the same holding temperature.And beyond the critical conditions the alignment degree Γof MnBi phase was increased with the increase of the holding temperature and the magnetic flux densty.The theoretic analyses combined with the experimental results show that the MnBi crystals in Bi-Mn alloy rotate to align along the magnetic field.The orientation of the crystal is promoted mainly by the magnetic moment due to the magnetic anisotropic crystal magnetizes in the field and impedes mainly by the impact between the crystals during their rotation.
ZHENG Wen-wei, CHEN Zhao-hui, FANG Hui, MA Qing-song. Fabrication of Cf/Si3N4 Composites by Different Pyrolysis Heating Rates[J]. Journal of Materials Engineering, 2002, 0(11): 22-24,28.
Three dimensional braided carbon fiber(3DBCf)reinforced Si3N4 composites were fabricated via infiltration and pyrolysis of polysilazanes(PSZ)by different heating rates.The results show that the mechanical properties of ceramic matrix composites can be enhanced markedly if the pyrolysis heating rates is increased The flexural strength of ceramic matrix composites which were fabricated by 10℃/min pyrolysis heating rate is 604MPa.
DU Jun, LIU Yao-hui, ZHU Xian-yong, YU Si-rong. Fabrication of Aluminum Alloy Matrix Hybrid Composites andits Optimization of Heat-treatment Parameters[J]. Journal of Materials Engineering, 2002, 0(11): 25-28.
Al2O3f/Cf/AlSi12CuMgNi short fibers reinforced hybrid metal matrix composites were fabricated by preform infiltrated route.The effects of solution and aging times on mechanical properties of the hybrid composites were investigated and heat treatment parameters were optimized.The results show that two kinds of fibers were distributed uniformly in the hybrid composites.Matrix structure becomes finer and more uniform after heat-treatment.The effects of heat-treatment parameters on mechanical properties of the hybrid composites are mainly controlled by three factors,namely the change of Si phase shape and size,degree of interfacial reaction and aging state.Optimum heat-treatment parameters are solution at 510℃/1h and aging at 170℃/4～8h.The fracture mechanisms of the hybrid composites is induced by debonding of reinforcing fibers at the large angle to the direction of the tensile load.
WANG Hua, YU Jun, WANG Yun-bo, NI Er-hu. Temperature Effects on Microstructure of Bi4Ti3O12 Ferroelectric Thin Films on Si Substrates[J]. Journal of Materials Engineering, 2002, 0(11): 29-31,47.
The ferroelectric thin films of Bi4Ti3O12on Sisubstrates were fabricated by Sol-Gel-technique.The effects of the annealing temperature on crystal phase,grain size and surface morphology of Bi4Ti3O12ferroelectric thin films were studied.The results indicate that the Bi4Ti3O12thin films are amorphous when the annealing temperature is below 450℃,and the Bi4Ti3O12thin films are polycrystalline when the annealing temperatures are from 550℃ to 850℃.Furthermore,the Bi4Ti3O12has a higher degree of texture or prefers orientation in the c axis with the increase of the annealing temperature,the grain size and surface roughness increase with the increase of the anneal-ing temperature as well.
ZHAO Zhan-kui, LI Jian-chen, JIANG Qing. Microstructure of Amorphous and Nanocrystalline Al65Si35 Alloy Prepared by Supercooling[J]. Journal of Materials Engineering, 2002, 0(11): 32-34.
Ribbon of Al65Si35(atom fraction/%)alloy in a thickness of 0.02～0.03mm and a width about 2mm was prepared by melt spinning method The structure of the alloy is investigated by transmission electron microscope(TEM),energy dispersive spectrometer(EDS)and Xray diffraction(XRD).The results show that the structure of the alloy consists of amorphous phase and nanostructured crystals.The Vickers hardness of alloys is HV230.
HUANG Yong-ling. Investigation on Artificial Joint Coated by Hydroxyapatite[J]. Journal of Materials Engineering, 2002, 0(11): 35-37.
The effect of hydroxyapatite on bone growth was studied.The cause of hydroxyapatite coating drop out from artificial joint resulted by bone cement improperly filling was analyzed The results show that both coating zone and non-coating zone are needed on artificial joint The bone cement should be only filled into non-coating zone On the coating zone,the hydroxyapatite coating need to closed coat on bone structure The artificial joint containing of coating zone and non-coating zone is not only utilizing the biological fixation and effect on bone growth of hydroxyapatite, but also favor to temporary mechanical fixation and long time biological fixation after operation.
LIANG Xiu-bing, DENG Zhi-chang, XU Yi, XU Bin-shi. Thermal Spraying Nanoscale Powder Materials and Coatings[J]. Journal of Materials Engineering, 2002, 0(11): 38-41.
Presently,thermal spraying of nanoscale powder materials has been the current in the field of thermal spraying with the development of nano science and technology. In this paper, preparing methods of nanoscale structure feedstock abroad and some nanoscale structure coatings prepared by advanced thermal spraying technologies are introduced.The development of nanocrystalline and amorphous grain structure coating is the most important of all.Compared with traditional coatings,nanoscale structure coatings showed super performances and excellent prospects of application in fields of anti-abrasion and anti-corrosion.
CHEN De-ming, WANG Ting-jie, YU Shan-jiang, JIN Yong. The Properties, Applications and Preparations of Nanometer TiO2 Particles[J]. Journal of Materials Engineering, 2002, 0(11): 42-47.
Nanometer TiO2particles have unique photo catalysis,excellent coloring effect and ultraviolet shielding function.There are promising application prospects in catalyst,cosmetics,anti-ultraviolet,functional ceramics,gas-sensitive sensors and so on-Many researches have focused on the properties, applications and preparations of nanometer TiO2 particles in recent years.In this paper, the research situation about the properties,applications and preparations of nanometer TiO2 particles are reviewed.
