LI Jing, YIN Yan-sheng, MA Hong-tao. Microstructure and Tribology Properties ofFe3Al Base Friction Material[J]. Journal of Materials Engineering, 2004, 0(8): 3-6,11.
A new kind of Fe3Al intermetallic base friction material was prepared by hot pressing. The microstrucure, mechanical properties and dry sliding friction and wear properties of this material were studied. The results show that the Fe3Al intermetallic based friction material has low density, high strength, high and smooth friction coefficient, and excellent wear resistance at high temperature. There are different wear mechanisms at different conditions. Under light loads the main wear mechanisms include abrasive wear and fatigue wear, which are characterized with microploughing and concavities. Under heavy loads the wear mechanisms include serious plastic deformation, crack propagation and fatigue fracture at the former stage of the friction, and oxidation wear at the later stage.
WANG Kai-guo, LI Jia-rong, LIU Shi-zhong, CAO Chun-xiao. Study on Creep Properties of SingleCrystal Superalloy DD6 at 980℃[J]. Journal of Materials Engineering, 2004, 0(8): 7-11.
The creep properties of the second generation single crystal superalloy DD6 with [001], [011] and [111] orientations were investigated under different stress at 980℃. The results show that single crystal superalloy DD6 has good creep properties. The creep properties of DD6 are anisotropic. The effect of stress on creep lifetime of the alloy with [001] orientation is lower than that with [011] and [111] orientations. The deviation degree between stress axial and [001] crystallizing orientation gradually decreases during creep, while deviation degree between stress axial and [011], [111] crystallizing orientations increases due to lattice rotation. The alloy with [001] orientation has higher working-hardening tendency than that with [011] and [111] orientations.
ZHANG Wei-ping, LIU Shuo, JI Shou-hua, MA Yu-tao. Research on Behavior of Grain Refinement in Metal-ceramicSurface Fine Composite Coating by Laser Cladding[J]. Journal of Materials Engineering, 2004, 0(8): 12-16,24.
In-situ synthesized TiB2/Fe metal-ceramic fine grain composite coating was fabricated on medium carbon steel by laser cladding with the optimal laser parameters, and a little amount of Fe2B, TiB hardy phase was incorporated in the coating. Microstructure of the coating was prominently refined compared with that of the substrate. The results show that the grain refinement behavior is closely related to the non-equilibrium rapid solidification process of laser cladding and the increasing of the inhomogeneous nucleation induced by the in-situ synthesis of the fine hardy particles. In addition, refinement of the substructure caused by the strong movement of the dislocation in the bonding metal matrix accelerates the grain refinement simultaneously. The fine structure is extremely beneficial to the improvement of the coating's properties.
REN Cheng-qiang, LIU Dao-xin, BAI Zhen-quan, LI Tie-hu. Study on Mechanical Properties of CorrosionScale on Surface of Tubular Steel N80[J]. Journal of Materials Engineering, 2004, 0(8): 17-20,24.
The hardness and bonding strength of corrosion scale on the surface of N80 steel, as tubular goods, were studied in different conditions. The effects of temperature, gas pressure and inhibitor on the hardness and bonding strength were discussed. It was found that the corrosion rate of N80 steel decreased with increasing hardness and bounding strength of corrosion scale.The quantitative equations of hardness, bounding strength and corrosion rate were put forward. To decrease the corrosion rate of steel, the mechanical properties of corrosion scale must be higher than certain critical values. Suitable inhibitors can be used to control corrosion of tubular steel by improving mechanical properties of corrosion scale.
XU Li-hua, XU Xiang-jun, LIN Jun-pin, WANG Yan-li, SONG Xi-ping, LIN Zhi, CHEN Guo-liang, LI Shu-suo, SU Xi-kong, HAN Ya-fang. Effect of Canned Forging on Microstructureof High Nb-containing TiAl Alloy[J]. Journal of Materials Engineering, 2004, 0(8): 21-24.
The as-cast nearly lamellar microstructure of high Nb-containing TiAl alloy were refined by means of two-step canned forging processing route. The results show that the pancake near surface after two-step forging is mainly banded lamellar microstructure with small part of recrystallized grains, and the rest of pancake is basically compound of uniform and fine recrystallized grains. The β phase can be efficiently eliminated, and the duplex microstructure can be gained by subsequent heat treatment at (α+γ) dual-phase region.
NIU Qing-yong, CAI Li-xun, LIU Yu-jie. Study on Uniaxial Ratcheting Modeling of1Cr18Ni9Ti Stainless Steel[J]. Journal of Materials Engineering, 2004, 0(8): 25-28.
Series of uniaxial ratcheting experiments of 1Cr18Ni9Ti stainless steel were carried out at room temperature. The influence of mean stress,maximum stress and the histories of ratcheting on the saturated ratcheting (SR) strain were investigated. The results show that the SR strain varies monotonously with the maximum true stress when the mean stress exceeds a certain value,the preceding ratcheting histories with lower maximum stress have no influence on the following SR strain with higher maximum stress. A model simulating the evolution of ratcheting strain at room temperature is presented, as well as a model for predicting the SR strain. Comparing with the experimental results, the prediction of the developed models is proved to be well.
LIU Jian-hua, SHANG Hai-bo, TAO Bin-wu, LI Song-mei. Corrosion Behavior of High Strength Steels 0Cr18Ni5 and AF1410[J]. Journal of Materials Engineering, 2004, 0(8): 29-31.
Corrosion resistance of two high strength steels in neutral salt spray test (NSST) was studied by mass loss and X-ray diffraction (XRD).Pitting corrosion was found on the surface of 0Cr18Ni5 steel, and severe general corrosion on the surface of AF1410 steel. The susceptibility to stress corrosion cracking (SCC) of the two steels in 3.5% NaCl (mass fraction) solutions was studied by constant load tensile and loss of strength and ductility. Both of the steels exhibited susceptibility to SCC.A simple method for evaluating SCC resistance of materials was put forward.
PENG Jian, ZHANG Ding-fei, YANG Chun-mei, DING Pei-dao. Homogenizing Research on ZK60 Magnesium Alloy Ingot[J]. Journal of Materials Engineering, 2004, 0(8): 32-35,53.
By means of metallography analysis and micro-hardness measurement,the microstructures and micro-hardness values of ZK60 magnesium alloy,annealed at different temperatures for different times,were compared.The effect of annealing temperature and time on structure transformation and composition homogenization was analyed.The results shown that the annealing temperature played a main role in homogenizing of ZK60 alloy.The optimized annealing process of ZK60 magnesium alloy,that is 470℃×14h,was suggested.
HUANG Xin-bo, JIA Jian-yuan, LIN Hua-chun, KANG Chun-xia. Corrosion Resistance and Wear Resistance of VFS CobaltBased Alloy-Tungsten Carbide Composite Coating[J]. Journal of Materials Engineering, 2004, 0(8): 36-38,43.
The cobalt based alloy-tungsten carbide composite coating bonded strongly with steel matrix was made by a vacuum fusion sintering(VFS) method. A series of experiments on the cobalt based composite coatings with the different tungsten carbide percent were performed by a pin-on-disc abrasion machine. The vibration corrosion resistance of the composite coating in hydrochloric acid (10%HCl) and sodium-hydroxide solution (10%NaOH) was experimented by the self-design vibration device. The results show that the wear resistance of the cobalt based composite coatings are prior to that of the 45# hardened steel, and that the higher the tungsten carbide percent, the better is the wear resistance. The corrosion resistance of the composite coating is much higher than that of the 45# hardened steel.
CHENG Xiang-zhen, SONG Yong-cai, XIE Zheng-fang, XIAO Jia-yu, Wang Ying-de. Synthesis of Polycarbosilane from Polydimethylsilane atHigh Temperature and High Pressure[J]. Journal of Materials Engineering, 2004, 0(8): 39-43.
The polycarbosilane (PCS), the precursor of SiC fiber, was synthesized at high temperature and high pressure by thermal decomposition of polydimethylsilane (PDMS). The influence of synthesis conditions on final pressure at room temperature, Si-H bond content, PCS yield, softening point, the molecular weight and distributions, and spinnability were investigated. The results show that the molecular weight and softening point of PCS increase while the reaction temperature increase The spinnability of PCS decreases gradually with temperature. Suitable reaction time for the synthesis of PCS from PDMS in autoclave should be 4～6h at 460℃, or 6～7h at 450℃. The as-synthesized PCS, in which the high molecular weight content was about 5%～10%(mass fraction) with softening point about 200 to 220℃, Si-H bond content more than 0.9, and good spinnability, was the suitable precursor for the preparation of SiC fiber.
LIU Xiao-guang, CHEN Da-ming, TONG Jian-feng, LI Bao-wei. Effect of Sintering Temperature on Microstructure andProperties of 8% Yttria Stabilized Zirconia[J]. Journal of Materials Engineering, 2004, 0(8): 44-46,50.
A 8% (mol fraction) yttria stabilized zirconia (YSZ) was shaped by aqueous gel casting. Effects of sintering temperature on shrinking rate, density, phase structure, microstructure and mechanical properties of the YSZ were studied. The results shown that shrinking rate and density increased with increasing sintering temperature. There was a little m-ZrO2 in the YSZ when sintering temperature was low. When green bodies were sintered at 1600℃ for 4h, m-ZrO2 changed into cubic fluorite structure. Straight grain boundary and well-grown grains were shown, and bending strength reached as high as 250MPa after sintering at 1600℃.
YE Bin, HE Xin-bo, QU Xuan-hui, QIN Ming-li, HU Xue-sheng. Effect of Fabrication Methods on MechanicalProperties of Cf/SiC Composites[J]. Journal of Materials Engineering, 2004, 0(8): 47-50.
Carbon fiber reinforced SiC composites were prepared by precursor pyrolysis-hot pressing (PP-HP) and precursor impregnation-pyrolysis (PIP).The effect of different fabrication methods on the microstructure and mechanical properties of the composites was investigated. It was found that the composite prepared by PP-HP exhibited a brittle fracture behavior, which was mainly ascribed to a strongly bonded fiber/matrix interface and the degradation of the fibers caused by a higher processing temperature. On the contrary, the composite prepared by PIP showed a tough fracture behavior, which could be rationalized on the basis of a weakly bonded fiber/matrix interface as well as a higher strength retention of the fibers resulting from a lower processing temperature.In comparison with the composite prepared by PP-HP, the composite prepared by PIP achieved better mechanical properties with flexural strength of 573.4MPa and fracture toughness of 17.2MPa·m1/2.
HUANG Guan-bao, ZHOU Ying, WU Rong-rui, XU Xi. Study on Properties of PEN-PET Copolyester Film[J]. Journal of Materials Engineering, 2004, 0(8): 51-53.
Several PEN-PET copolyester films were prepared. The shrinking property, the sonic orientation property and mechanical property of these films were studied.The results show that the increasing of the PEN content results in decrease of the shrinking,increase of the oriental factor, and decrease of the breaking elongation.
QIAO Bao-wei, LIU Zheng-tang. Advance in Research on Anti-oxidation Optical Coatingsfor Protection of Diamond[J]. Journal of Materials Engineering, 2004, 0(8): 54-56.
High temperature failure mechanism of diamond was reviewed. Several anti-oxidation optical coatings of diamond under development, such as AlN coating and Y2O3 coating, were presented. The key problems, to be solved in future studies, of anti-oxidation and optical coating for high speed or high temperature applications were suggested.
MA Li-ting, CHEN Xin-wen, SU Bin. Research Progress in Aeronautical Perspex Aging[J]. Journal of Materials Engineering, 2004, 0(8): 57-59,64.
The research progress of the aeronautical perspex aging is presented including aging properties, experimental method, and atmospheric aging lifetime. The research works in this field, which should be done in the future, are shown.
GUO Xu-tao, LI Pei-jie, XIONG Yu-hua, LIU Shu-xun, ZENG Da-ben. Application of Rare Earth in Aluminumand Magnesium Alloys[J]. Journal of Materials Engineering, 2004, 0(8): 60-64.
The addition of rare earth(RE) as trace elements to aluminum or magnesium alloys can purify the melts,refine and modify the microstructure,reduce the inclusion. The addition of more RE elements can significantly enhance the comprehensive properties,especially mechanical behavior at high temperature. Research, development, and application for RE-containing Al alloys and RE-containing Mg alloys is reviewed with the emphasis on the effect of RE elements on melting,processing, and alloying of alloys. The future development of RE-containing Al alloys and RE-containing Mg alloys is prospected.
