YU Hui-chen, XIE Shi-shu, ZHAO Guang-pu, YANG Hong-cai. High Temperature Tensile and Creep Rupture Properties in Ni-based Superalloy GH141[J]. Journal of Materials Engineering, 2003, 0(9): 3-6.
The effects of heat treatment on tensile properties at 760℃ and stress rupture at 900℃ in Ni-based superalloy GH141 were investigated. The relationship between microstructures and mechanical behaviors at elevated temperature was discussed. The results show that the relationship between grain size and tensile strength still follows Hall-Petch law,and the strengthening γ′phases can be described by the model in which dislocation overcome γ′ phases from cutting.to by passing. The type and amounts of grain-boundary carbides have a very deep influence on rupture life. The strength balance between grain-boundaries and inside grains is also very important for the life of alloy.
DONG Jian-xin, LI Ang, ZHANG Mai-cang. Thermodynamic Simulation of Precipitations in GH586 Superalloy[J]. Journal of Materials Engineering, 2003, 0(9): 7-10.
Using a thermodynamic Thermo-Calc software and relevant Ni-base superalloy database, equilibrium precipitate phases and the effect of the chemical compositions on the precipitation regulation were studied in GH586 superalloy The calculation results provide the theoretic basis on utilizing the structure potential and improving the use characteristics of this alloy.
AO Hong-rui, JIANG Hong-yuan, WANG Shu-guo, XIA Yu-hong, JIA Chang-hai, A. M. Ulanov. Experimental Research on Anisotropic Characteristics of Elastic Damping Elements of Metal Rubber[J]. Journal of Materials Engineering, 2003, 0(9): 11-14.
The anisotropical characteristics of metal rubber (MR) elements performed under loadings in different directions were researched, and physical hypothesis were provided for the analysis of inner structure of metal rubber material. The main parameters for the analysis of anisotropical performance were confirmed according to the previous hypothesis and tested experimentally. The results show that variety of the relative heights and the radius of MR elements affect the radial stiffness of MR isolator. When isolator works in radial direction, the linear mechanical characteristics are available. If there are several MR isolators with pressure loading in the isolation system, it also can bear the perpendicular loading to the forming force. Compared with steel cylindrical elements, the MR elements with the same structure and size show the same tendency of stiffness change when shear force is loaded.
ZAN Qing-feng, WANG Chang-an, HUANG Yong, LI Cui-wei, ZHAO Shi-ke. Preparation and Properties of Al2O3/Ti3SiC2 Multilayer Materials[J]. Journal of Materials Engineering, 2003, 0(9): 15-17,21.
The Al2O3/Ti3SiC2 multilayer materials were prepared by two methods. One is the in situ HP that means the Ti3SiC2 layer is in situ synthesized from the Ti, SiC and C powders during the preparation of the multilayer materials; the other is multistep that the pre-synthesized Ti3SiC2 powders are used to prepare multilayer materials. For the Al2O3/Ti3SiC2 multilayer materials by the two methods, work of fracture was improved by over tenfold than Al2O3 materials as well flexural strength keeping above 450MPa. Moreover,the different composition and microstructure was obtained by different preparation procedure, and of course some difference in mechanical properties also existed, such as the flexural strength of the multilayer materials by in situ HP was higher and the toughness was lower.
ZHANG Fu-qin, HUANG Qi-zhong, HUANG Bai-yun, XIONG Xiang. Relationship between Thermal Conductivity and Graphitization Degree of a Chopped Carbon Fiber/Resin-derived Carbon Composite[J]. Journal of Materials Engineering, 2003, 0(9): 18-21.
The relationship between the thermal conductivity and graphitization degree of a chopped mesophase pitch-derived carbon fiber/resin-derived carbon composite was investigated by laser flash method and XRD.A mathematical model was founded, which was interpreted by phonon heat conduction mechanism The results show that though the thermal conductivity λ in the direction parallel to the layer orientation is about six times of that in the direction vertical to the layer orientation,the value of the two increases with the increase of the graphitization degree g(and the stacking height of the crystallite) of the composite, and their relations can be written into the following equations:respectively λ=53.78+0.28exp(g/13.75) and λ=4.95+0.94exp(g/25.22) respectively.
WANG Yu-quan, LI Ming, SUN Li, DENG Hai-jin. Studies on Magnetoresistance Character of Woven Fabric Carbon/Carbon Composites[J]. Journal of Materials Engineering, 2003, 0(9): 22-25.
The carbon/carbon composites with cloth precursor were graphitized at various heat treatment temperature (HTT) and their graphitization degree g was determined by X ray diffraction method. The magnetoresistance (MR) properties as functions of orientation angle (φ),measurement temperature (MT) and magnetic field (B) were investigated.The results show that under the experimental conditions, the increase of graphitization degree results in the increase of composites magnetoresistance,but has no effect on the relation of MR with orientation, which is also not affected by measurement temperature and magnetic field intensity.MR decreases linearly with the increase of measurement temperature at 5~300K in a constant magnetic field intensity.In the range of 0~1.2 T, MR increases with the increase of the magnetic field intensity in the temperature area of 5~300K, until above 1.2T,MR no longer risen At 4.2K, the MR,which is changed with magnetic field, presents quantum phenomenon.
ZHENG Jun-ping, XI Li-fei, YANG Xue-wen, YAO Kang-de. Mechanical Properties of Gelatin and Gelatin/Montmorillonite Nanocomposite Crosslinked via Different Methods[J]. Journal of Materials Engineering, 2003, 0(9): 26-29.
Influence of glutaraldehyde (GLA) vapor crosslink, solution crosslink and dextran dialdehydes solution crosslink on the mechanical properties of gelatin and gelatin/montmorillonite (MMT) nanocomposite was investigated. Fracture surfaces of the samples were observed by scanning electron microscopy (SEM). The results show that compared with solution crosslink, vapor crosslink could achieve higher crosslinking degree for gelatin material. GLA has higher crosslinking efficiency than dextran dialdehydes and mechanical properties of samples are better at same concentration via solution crosslink Gelatin/MMT nanocomposite could not be prepared via GLA solution crosslink It is needed much time for vapor crosslink to reach certain crosslinking degree owing to the barrier property of MMT sheets Intercalated with MMT could improve mechanical properties of gelatin material significantly. SEM shows the improvement of toughness at the same time.
LIU Xiao-guang, LI Guo-jun, TONG Jian-feng, CHEN Da-ming. Study on Stability of Zirconia Aqueous Slurries[J]. Journal of Materials Engineering, 2003, 0(9): 30-32,29.
Aqueous slurries of 8%(mol fraction) yttria-stablized zirconia were firstly prepared Measurements and analytical methods to zeta potential, rheological properties, sediment experiment, SEM photographs of sediment particles were used for optimizing parameters.High dispersible and stable zirconia aqueous slurries are gained through adjusting pH value and dispersant content.
ZHU You-li, LIAO Han-lin, C. CODDET, LIANG Xiu-bing, XU Bin-shi. Cross Flying Behavior of Particles in Wire Arc Spray Process[J]. Journal of Materials Engineering, 2003, 0(9): 33-36,40.
Quantitative analysis of the microstructure of the mound of deposit arc sprayed revealed that there was a cross flying behavior of particles in the plume. Along the cross section of the deposit mound, flattened particles from the anode and cathode wires were distributed in an antisymmetric way about the centerline of the plume and varied gradually. For the deposits sprayed by an open nozzle system and a closed nozzle system with converging bore, the locations of the maximum particle density of the anode and cathode materials were not coincided with each other and were not located at the centerline of the plume. However, for the deposit sprayed with closed nozzle system with converging-diverging bore, such phenomenon was not obvious.
CHENG Yan, CAI Wei, ZHAO Lian-cheng. Effects of Cl- Concentration and pH on Corrosion Behaviour and Ni Release of TiNi Alloy[J]. Journal of Materials Engineering, 2003, 0(9): 37-40.
Corrosion behaviour and Ni ion release rate of a TiNi shape memory alloy in.NaCl solution at different Cl- concentration and pH value were studied by cyclic potentiodynamics anodic polarization and atomic adsorption spectrum measurements. The results show that the increase of pH value and the decrease of Cl- concentration results in better corrosion property and less releasing rate of Ni ion.
TANG Xin, YU Bao-zheng, HU He, ZHANG Shan-qing. Investigation on Hot Isostatic Pressing and Heat Treating Process for Control-grain Cast Integral Turbine Wheels of K418B Alloy[J]. Journal of Materials Engineering, 2003, 0(9): 41-43,47.
Hot isostatic pressing process and vacuum heat treating process were investigated for control-grain cast integral wheel of K418B alloy. Their process parameters were obtained. After hot isostatic pressing and vacuum heat treating, performance of the integral turbine wheel were improved greatly.
XI Shou-mou, ZHANG Jian-guo, SUN Xiao-yan, ZHANG Jin-sheng, LIU Fu-rong, WANG Zhi-gang. Laser Quenching + Nitriding Compound Treatment of 40CrNiMoA Steels[J]. Journal of Materials Engineering, 2003, 0(9): 44-47.
Laser quenching,nitriding,nitriding-laser quenching compound treatment and laser quenching-nitriding compound treatment on 40CrNiMoA steels was carried out, and its surface hardness was investigated.Comparing with the simple nitriding,the combining process of laser quenching-nitriding would increase the surface hardness by 100～200HV and the depth of hardened layer would be double. However, if the combining process of nitriding-laser quenching is employed,the depth of hardness layer would be much deeper than that of simple nitriding,while the surface hardness would not be increased.
