GAO Si, WANG Jun, WANG Yifei, WANG Ping, WANG Jianhua, LIU Yonghua. Preparation of Nano Titanium Dioxide Reinforced Rigid Polyurethane Foam[J]. Journal of Materials Engineering, 2004, 0(2): 3-5,9.
By power ultrasonic, nano titanium dioxide particles were dispersed into polyaryl-polymethylene-isocyanate(PAPI)and rigid polyurethane foams(RPU) reinforced by nano TiO2 were prepared by polymerization PAPI with polyether polyol. SEM was employed to observe structures of TiO2 filled polyurethane foam and showed that nano TiO2 particles had been dispersed uniformly in foam. Results of mechanic test show that nano TiO2 particles in low loading fraction could increase the compress strength and impact strength of rigid polyurethane foam. But addition of nano TiO2 led to the rapid accretion of viscosity of PAPI, which made the foam reaction difficult and contributed to the impact strength decrease in addition of 10% nano TiO2.
SONG Guangxiong, ZHANG Xiaoqing, CHANG Yanyan, ZHANG Zheng, ZHONG Qunpeng. Corrosion Failure Cases about Pressure Vessels and Pipes[J]. Journal of Materials Engineering, 2004, 0(2): 6-9.
To survey the situation of corrosion failure about pressure vessels and pipes, more than 400 reports and articles related are collected, which concern petro-chemical industry, chemical industry, petroleum industry. The parts that occur corrosion failure include container, piping, heat exchanger, boiler, vessel, tank. The corrosion failure modes concerned are hot corrosion, pit corrosion, crevice corrosion, galvanic corrosion, intergranular corrosion, selective corrosion, stress corrosion cracking, corrosion fatigue, hydrogen attacks, blistering, hydrogen induced cracking, impinging corrosion.
LI Chensha, LI Guitao, TIAN Qiu, ZHANG Shiji, TIAN Feng, WANG Dazhi, CAO Maosheng. Activation of Carbon Nanotubes by Air and CO2 and its Effect on Electric Double Layer Capacitors[J]. Journal of Materials Engineering, 2004, 0(2): 10-13,17.
Carbon Nanotubes (CNTs) were activated by CO2 and air under different durations, then were used in polarizable electrodes of electric double-layer capacitors (EDLCs). Experiment results indicated that air and CO2 activation could modify intrinsic structures and improve dispersity of CNTs. Specific capacitance of EDLCs based on activated CNTs were obviously improved and the equivalent series resistance decreased, but the effects were influenced by duration of activation process.
REN Yinglei, JIN Tao, GUAN Hengrong, HU Zhuangqi. Microstructure and Mechanical Properties of a Nickel Base Single Crystal Alloy Long Term Aged at High Temperature[J]. Journal of Materials Engineering, 2004, 0(2): 14-17.
The influence of microstructure after long time aging at high temperature on the stress rupture at 1010℃/248MPa was investigated. The results showed that the stress rupture properties of specimens after aging at 950℃ for less than 500h were not significantly changed, whereas the stress rupture properties were greatly reduced after aging for 1000 hours. Furthermore, the stress rupture properties begun to reduce significantly aged at 1050℃ for 500 hours due to the enlarged size of γ′phase and its anomalous sha pe. The γ′phases begun to grow at direction of [100] after the specimens aging at 950℃ for 500h and 1050℃ for 100h.The interfacial energy of γ/γ′phases and the reduction of elastic strain energy was the driving force for γ′phase's growth.
QIN Ming, YI Xiaosu. Study on the Forming Process and Electron Beam Irradiation Treatment of a Thermoplastic Controllable Crosslinking Poly (Aryl Ether Ketone) Matrix Composites[J]. Journal of Materials Engineering, 2004, 0(2): 18-21,25.
The forming process of a thermoplastic Controllable Crosslinking Poly(Aryl Ether Ketone)(CCPAEK) matrix composite was reported in this paper. The temperature and press program of the thermal forming process was confirmed through determining Melt Index (MI) of the CCPAEK at different temperatures. The electron beam (EB) irradiation character of the CCPAEK matrix was studied and the thermoplastic composite specimens were EB irradiated at a certain dosage. The influences of EB irradiation on the structure and properties of the composites were studied. The glass transition temperatures (Tg) of the irradiated couples were found enhanced limitedly by means of Differential Scanning Calorimeter (DSC) and Dynamic Mechanical Thermal Analysis (DMTA). The flexural strength of EB treated specimen increased while the flexural module and the short beam shear strength changed unobvious.Scanning Electron Microscope (SEM) showed that the irradiation had almost no influence on the interfacial structures of the composites.
QU Shaobo, WANG Shuwen, HAO Tao, XUE Jin, TIAN Changsheng. The Effect of Lead Deficiency on Ordered Micro-region,Dielectric and Electrostrictive Properties of PZN-based Ceramics[J]. Journal of Materials Engineering, 2004, 0(2): 22-25.
The effect of PbO deficiency in starting raw powders on the phase structure, ordered micro-regions, dielectric and electrostrictive properties of PZN-based ceramics was investigated. The results demonstrated that even minor content of PbO deficiency would result in pyrochlore phase in both calcined powders and sintered ceramics. With the increase of deficient PbO, the perovskite phase content decreased gradually. When the content of PbO deficiency is less than 1%,the size of ordered micro-region, dielectric constant and electrostrictive strain increased greatly with the increase of PbO deficiency. However, when PbO deficiency is more than 1%, PbO deficiency would result in the decrease of dielectric and electrostrictive properties. PbO deficiency only affected dielectric loss very weakly. The increase of dielectric constant and electrostrictive strain resulted from the enlargement of the size of effective ordered micro-regions and the elimination of PbO film among crystal borders.
ZHANG Xiaoyun, SUN Zhihua, TANG Zhihui, LIU Minghui, LI Bin. Study on Galvanic Corrosion and Protection between TA15 Titanium Alloy and Aluminum Alloys or Structural Steels[J]. Journal of Materials Engineering, 2004, 0(2): 26-28,31.
The galvanic corrosion of TA15 titanium alloy coupled with aluminum alloys and structural steels was studied by means of current density of couples. The result indicated that the galvanic corrosion between TA15 titanium alloy and aluminum alloys or 30CrMnSiA structural steel was serious, it is necessary to protect aluminum alloys and 30CrMnSiA structural steel when it is coupled with TA15 titanium alloy. There was little galvanic corrosion between TA15 titanium alloy and 30CrMnSiNi2A structural steel. The current density of couples could be decreased by surface treatment to aluminum alloys and structural steels, and decreased greatly by applying paint after surface treatment.
YAN Hongxia, NING Rongchang, MA Xiaoyan, HUANG Ying. Research on Tribology of Bismaleimide Materials Filled with Graphite and Namometer Si3N4[J]. Journal of Materials Engineering, 2004, 0(2): 29-31.
The bismaleimide composite materials filled with graphite and nanometer Si3N4 were made by casting method. The effects of graphite and nanometer Si3N4 content on tribological properties were evaluated. The morphology of the composite worn surface was studied by Scanning Electron Microscopy, and the wear mechanism of composite materials were also investigated. The result showed that nanometer Si3N4 have better effect on decreasing the friction and wear of bismaleimide polymer composites than graphite. Especially,the friction coefficient of the pair was lowered from 0.36 to 0.25 and the wear rate was lowered by 72% when the composite contain 1.5% (mass fraction) nanometer Si3N4.
LI Songmei, JIANG Weicang, LIU Jianhua, SUN Zhongzhi. Study on Corrosion Resistance of Aircraft Conduit Connector of T-31 Titanium Alloy at Simulated Service Environment[J]. Journal of Materials Engineering, 2004, 0(2): 32-36.
Corrosion resistance,airproof and oilproof property of aircraft conduit connector of T-31 titanium alloy were studied at simulated service environment by a conduit connector corrosion experiment system. The behaviors of surface corrosion and stress corrosion of the connectors were evaluated and the corrosion mechanism was investigated. The slight pitting was found just at stress focus place. The stress corrosion sensitivity of the connector was not observed at experiment stress level. It was proved that corrosion medium infiltrated the hole of anodic oxidation film and made the alloy corrosion slightly. The susceptibility of galvanic corrosion of stainless steels 1Cr18Ni9Ti contacted with titanium alloy T-31 in 6% NaCl solution was studied. It was showed that the galvanic corrosion current of galvanic couple was very low. It was demonstrated that the stainless steels 1Cr18Ni9Ti could be used to make the aircraft conduit to be connected with the connector made with T-31.
GUO Yalin, QIU Zheming, LIANG Guozheng. Study of a Rubber Mould for Lattice Structure[J]. Journal of Materials Engineering, 2004, 0(2): 37-39.
The study of a rubber mould for lattice structure was presented. The tensile strength, tensile elongation, specific heat, thermal conductivity, density, linear shrinkage and shore A hardness of the rubber were 1.11MPa, 95.6%, 2.068×103J/(kg·K), 0.224W/(m·K), 1.087×103kg/m3, 1.05% and 60 respectively. The forming processing of the rubber was good and a φ480 mould which can be used to wind a lattice structure was fabricated.
HE Lizi, SUN Xiaofeng, ZHENG Qi, HOU Guichen, ZHANG Chengzhong, GUAN Hengrong, HU Zhuangqi. Investigation of Carbides of M963 Nickel-base Cast Superalloy with High Content W[J]. Journal of Materials Engineering, 2004, 0(2): 40-43.
The type,morphology,distribution of carbides of M963 nickel-base superalloy with high content of W,Mo was investigated. According to the different thermodynamic conditions of carbides, the type of carbides of M963 alloy could be divided into inherited carbide, spontaneous nucleated carbide and precipitated carbide. The inherited coarse faceted MC-type carbide was the main carbide, located at grain boundaries or interdendritic regions. Once the melt homogenized, the Chinese script-type carbide in spontaneous nucleated eutectic appeared, the spontaneous nucleated non-eutectic blocky carbide appeared when the temperature is over 1850℃, the Chinese script-type carbide located at interdendritic regions. With the rise of temperature, the sequence of the morphology of carbide was: faceted→Chinese script→blocky, the carbide became smaller and distributed more uniformly.
ZHANG Meizhong, LI Hejun, LI Kezhi. Progressing in the Study on Mechanical Properties of the 3D Braided Composites[J]. Journal of Materials Engineering, 2004, 0(2): 44-48.
Recent developments on mechanical behaviors of 3D braided composites were reviewed. It was summarized that experiment, micro-structure modeling and numerical simulation are the mainly investigative methods. Experiment investigations concentrated on testing the mechanical properties of 3D braided composites with different braiding parameters and load. Micro-structure modeling based on the yarn topology in the preform, such as"*"type model, fiber inclination model and 3 cell model,were applied successively. Numerical simulation carried out by means of the finite element analysis, which is based on the line elastic mechanical properties of 3D braided composites. However, further work still is required before the mechanical properties are properly predicted. Some suggestions for future investigations were also made in this paper.
