XU Xiang-yang, LIU Shi-can, ZHANG Zhen-xue, XU Bin-shi, ZHOU Zhong-rong. A Study on Characteristics of Fretting Wear of Plasma Sprayed CoCrW Coating[J]. Journal of Materials Engineering, 2001, 0(3): 3-6.
The characteristics of fretting wear of plasma sprayed CoCrW coating was investigated. The results show that the fretting wear of plasma sprayed CoCrW coating can be divided into three stages, which are respectively initial, transient and steady stages. The main fretting wear mechanism is respectively adhesion, oxidation and fatigue wear. The high fretting wear resistance of plasma sprayed CoCrW coating results from its moderate hardness and excellent toughness.
XIAO Yong, HU Ke-ao, WU Ren-jie. Preparation and Property of Polyethylene Oxide/LixMoO3 Nanocomposite[J]. Journal of Materials Engineering, 2001, 0(3): 7-9.
PEO/LixMoO3 nanocomposite was prepared by solution intercalation method. Powder X-ray diffraction and differential scanning calorimetry show that PEO chains are intercalated into LixMoO3galleries. Electrochemical Property of LixMoO3 is improved after PEO intercalation.
MA Ya-lu, SUN Xiao-bing, ZHENG Jun-ping, YUAN Qi-ming. Preparation and Properties of Fine-grained(Ce,Mg)-PSZ/MgAl2O4 Ceramics[J]. Journal of Materials Engineering, 2001, 0(3): 10-12,15.
Powders were prepared by mechanical milling-mixing process, in which industrial zirconia was used as the main starting material and CeO2,MgO as co-stabilizing agents and α-Al2O3 as particle additions. Fine-grained PSZ ceramics sintered at low solid solution temperature(≤1550℃)and annealed at 1100℃ had good mechanical properties:the flexural strength and fracture toughness at room temperature were about 655MPa and 15MPa·m1/2, respectively. The critical temperature of thermal-shock resistance was about 750℃, which attribute to microcrack toughening mechanism. After hydrothermal treatment(180℃,1MPa, in distilled water) up to 20h,(Ce,Mg)-PSZ/MgAl2O4 ceramics exhibited much better hydrothermal stability.
LIU Pei-sheng, LIANG Kai-ming, GU Shou-ren, SUN Xiao-feng, GUAN Heng-rong, JIN Tao, YANG Ke-nu. Main Degradation Way of Aluminide Coating on Co-base Superalloys Oxidized in Air at High Temperatures[J]. Journal of Materials Engineering, 2001, 0(3): 13-15.
The structure change was observed and analyzed for the aluminide coating on a representative Co-base superalloy DZ40M during high-temperature oxidation in air. It is discovered that, this coating, which is prepared by low-pressure chemical vapor deposition(LP-CVD), degrades mainly by oxidation on the surface of the coating at 900℃, but mainly by inner-diffusion of Al inward to the substrate at 1000℃.
GUO Fu-an, YANG Jun, ZHENG Rui-ting, ZHANG Yong-gang, V. Ji. Micro-mechanics Analysis of Strength of Near γ Microstructure of TiAl-based Intermetallic Alloys[J]. Journal of Materials Engineering, 2001, 0(3): 16-19,22.
In order to study the influence of the volume fraction of α2 phase on the mechanical properties of TiAl-based intermetallic alloys, room-temperature tensile test was carried out on a series of near γ TiAl alloys with different volume fractions of α2 phase due to different Al contents, then a micro-mechanics model was employed to analysis the mechanical properties of these alloys. There-sults show that the volume fraction of α2 phase has a strong effect on the mechanical properties of near γ alloys, and the calculated results are in good agreement with the experiment, the difference of calculated and experimetal results was also discussed.
CHEN Li-xin, WANG Ru-min, LAN Li-wen, ZHENG Ya-ping. Study on Modifying Epoxy Resin with Liquid Crystalline Epoxy by in-situ Polymerization[J]. Journal of Materials Engineering, 2001, 0(3): 20-22.
The epoxy resin(CYD-128) modified by in-situ polymerized liquid crystialline epoxy(PHBHQ) has been discussed. The results show that the epoxy resin impact strength can be enhanced greatly with the content of PHBHQ increasing and other properties are enhanced to varying degrees too. The microstructure of PHBHQ/CYD-128 compound has been observed by SEM.
LI Ling-jie, LI Di, ZHANG Sheng-tao. The Deposition Mechanism of Cerium on Oxide Coatings of Aluminum Alloy[J]. Journal of Materials Engineering, 2001, 0(3): 23-24,27.
The process of anodic oxidation of aluminum alloy in sulfuric acid solution as well as that of cathodic polarization of anodic oxide coatings in solution containing cerium salt were studied using in-situ ellipsometry. The results show that the composition of the oxide film is affected by cathodic polarization and cerium could deposit on the film surfaces.The deposition of cerium is sensitive to the solution pH, the lower the pH, the less cerium deposited.
LI Ning, LI De-yu, ZHAI Shu-fang, WANG Chun-guang. The Anti-oxidation and Abrasion Performance in High Temperature of Ni-P/CaF2 Composite Coating[J]. Journal of Materials Engineering, 2001, 0(3): 25-27.
The electroless Ni-P/CaF2 coating, which combines the anti-oxidation performance of electroless Ni-P coating with the self greasy property of CaF2 in high temperature was designed. A testing machine was also designed to measure its abrasion performance in high temperature. It is shown that Ni-P/CaF2 has good performance. Moreover, the abraded quantity of coating is decreased with the increasing of testing temperature under 700℃.
MA Ming-zhen, YU Jin-ku, ZHAO Yu-cheng, ZENG Song-yan. Microstructure and Mechanical Properties of in situ TiCP/LD7 Composites[J]. Journal of Materials Engineering, 2001, 0(3): 28-30.
The in-situ TiCP/LD7 composites were prepared by reaction synthesize technique, and it was the stick of φ12 mm by thermal extrusion. The ultimate tensile strength(σb,σs), elastic modules(E) and elongation(δ) of the in-situ TiCP/LD7 composites was tested at the heat treatment condition of T6. The microstructure of the in-situ extruded TiCP/LD7 composites was observed by the use of SEM, and the fracture morphology was also observed. The results show that the ultimate tensile strength and the elastic modules of the in-situ TiCP/LD7 composite with 20wt%TiCP are 417MPa,373MPa and 92GPa respectively, and the elongation is up to 4.5%, the fracture is ductile.
CUI Li-shan, ZHENG Yan-jun, YANG Da-zhi. The Constrained Reverse Martensitic Transformation Characteristic of NiTi Shape Memory Alloy Fiber Embedded in Al Matrix[J]. Journal of Materials Engineering, 2001, 0(3): 31-34.
The constrained reverse martensitic transformation characteristic of NiTi shape memory alloy fiber embedded in Al matrix was studied by DSC, XRD and SEM. Results show that two kinds of reverse martensitic transformation appeared in the embedded NiTi fibers after prestrain, those are, the reverse transformation of thermal-induced martensite(MT→P) and that of stress-induced martensite(Md→P). The characteristic temperatures of the reverse transformation of thermal-induced martensite are very close to that of unprestrained specimens, and are not influenced by prestrain. The characteristic temperatures of the reverse transformation of stress-induced martensite increases with the increasing degree of prestrain. The amount of transformed thermal-and stress-induced martensite decreases with the increasing degree of prestrain. The concept of the deformation degree was introduced in this paper, and the variation of the deformation degree of stress-induced martensite during the reverse transformation process was discussed.
XU Xing-li, MA Li-guo, DAI Jian-qing, ZHOU Long-jie, HUANG Yong, XIE Zhi-peng. Microstructure and Properties of Si3N4 Based on Gelcasting[J]. Journal of Materials Engineering, 2001, 0(3): 35-36.
The forming process of gelcasting is one of the important in-situ forming techniques, which can effectively increase materials reliability and lower the manufacturing costs of complex-shaped ceramic parts. Based on gelcasting of Si3N4, Two-step gas pressure sintering of Si3N4 is made in this paper. Their room temperature bending strength can reach 958±41.8MPa,fracture toughness can reach 9.6MPa·m1/2,Weibull modulus can reach 23. Si3N4 ceramics obtained exhibits a bimodal microstructure composed of large elongated grains dispersed in a fined-grained matrix.
ZHAO Jia-xiang. New Technique for Manufacturing Graphite Fibers——Radio-frequency Direct-heating Method[J]. Journal of Materials Engineering, 2001, 0(3): 37-38.
New progress on developing graphite fibers——Radio-frequency Direct-heating Method was introduced. The disadvantages of traditional graphitization technology,the principals, characteristics and advantages of new method were pointed out. The properties of graphite fibers produced by new technique were also reported.
QI Bao-sen, YAO Xin, WANG Cheng-guo, XU Ying. A Study of Al Coating on Bearing Ball by High Energy Ball Milling[J]. Journal of Materials Engineering, 2001, 0(3): 39-41.
The microstructure and phase structure of Al coating on GCr15 bearing ball by high energy mechanical ball milling was probed, and this variation of annealing coating was analyzed.
YU Qing-chun, HUANG Hai-yan, ZHU Qin-wei, WU Yi-hua. New Method for Preparation of PEG/VXG Nanocomposite[J]. Journal of Materials Engineering, 2001, 0(3): 42-44.
A new method for preparation of PEG/VXG nanocomposite was introduced-Using decavanadic acid as initiator, PEG was intercalating into the layers of V2O5 while VXG was forming.The layered distance can be controlled by the content of PEG-This is a new idea for studing the interface of nanocomposite-The experiment shows that PEG/VXG nanocomposite keeps the layer structure of VXG and increases the layered distance but decreases the ordered zone.
HAN Qing-rong, CHEN Xiao-ming. Bioactive Ceramic Coatings Prepared by Electrodeposition[J]. Journal of Materials Engineering, 2001, 0(3): 45-48.
This paper introduces the preparation methods of bioactive ceramic coatings on Ti or titanium alloy by electrodeposition including electrophoretic deposition(EPD) and electrochemical deposition(ECD), reviews the main controlled parameters.The merits and application prospects of this technique are also presented.
