ZHANG Zeng-zhi, HAN Gui-quan, FU Yao-wen, SHEN Li-shan. Analysis on Microstructure of Ni60 Coating by High and Medium Frequency Induction Cladding[J]. Journal of Materials Engineering, 2003, 0(4): 3-5.
The microstructure of Ni60 coating by high-frequency induction cladding and medium-frequency induction cladding was analyzed. The results show that the metallurgical combination is formed between Ni60 coating and base,while diffusion and transfer coat can be observed obviously. The microstructure of Ni60 by high-frequency induction cladding is even and detailed. There are a lot of hardness phases which can enhance abrasion-performance. By contrast, The Ni60 coating by medium-frequency induction cladding is mainly composed of the needle-shape microstructure and has a greater inclination to form the zone of lacking chromium.
ZHANG Jing-de, YIN Yan-sheng, ZHANG Hong, LI Jing. Research on the Properties of Fe3Al-Al2O3 Graded Coatings[J]. Journal of Materials Engineering, 2003, 0(4): 6-9.
Fe3Al-Al2O3 coatings with different types of composition were fabricated by plasma spraying.The microstructure and the distribution of composition were analyzed by means of XRD, SED and EPMA, the adhesion strength, microhardness and thermal shook resistance were tested. The results show that the Fe3Al transition layer can benefit to the properties of coatings. Fe3Al intermetallic is a kind of excellent transient materials when spraying ceramics coatings on carbon steel substrate. The gradual distribution of composition improves the adhesion strength and thermal shook resistance.
ZHONG Hai-sheng, LI Qiang, ZHAO Shi-xi, SONG Feng-bing, LIChun-hong. Effect of Excess PbO and MgO on the Fabrication of PMN-PT Relaxor Perovskite Structure Phase[J]. Journal of Materials Engineering, 2003, 0(4): 10-11,20.
The perovskite phase of (1-x)PMN-xPT(0≤x≤1)has been synthesized by precursor method.As it showed by the XRD,the excess of PbO and MgO is helpful to forming perovskite (1-x)PMN-xPT.Pure perovskite (1-x)PMN-xPT can be synthesized at very low temperature,and therefore volatilization of PbO can be reduced.
LIU Ruo-yu, FANG Qing-qi. Transformation Study of Sol-gel Precursors of Mullite[J]. Journal of Materials Engineering, 2003, 0(4): 12-13.
A precursor gel with stoichiometric mullite composition (Al2O3;SiO2=3;2) was prepared by alkoxide hydrolysis of tetraethoxysilane (TEOS) and aluminum isopropoxide (Al(OC3H7)3) in amine solution.The mixture was then gelled in a 120℃ oven for 18h and ground into powders Some of the powders were calcined at 500℃,1000℃,1100℃ and 1200℃ respectively for 2h for study. The formation of mullite (3Al2O3·2SiO2) from these sol-gel derived precursor powders was studied using differential thermal analysis (DTA) and X-ray diffraction (XRD) method. It is concluded that, with the increase of temperature, the phases precipitated from the noncrystalline gel are successively cubic gamma-Al2O3, hexagonal alpha Al2O3, and orthorombic mullite As confirmed by the experimental results,the prepared gel powder can be transformed into mullite at a temperature as low as 1100~1200℃.
LI Ai-bin, GENG Lin, ZHAI Jin-fan. Effect of Whisker Orientation on the Hot Compressive Deformation Behavior of SiCw/Al Composites[J]. Journal of Materials Engineering, 2003, 0(4): 14-16,43.
The effect of whisker orientation on the hot compressive deformation behavior of SiCw/6061Al composites at 300℃ is investigated by means of SEM and Magiscan-2A image analysis system. The experimental results show that the whisker behaviors including whisker rotation and breakage are rather sensitive to the whisker orientation. With increasing the whisker orientation angle, the strain softening effect induced by the rotation and breakage of the whiskers decreases. Meanwhile, the whisker orientation affects the shapes of the stress-strain curves of the composites. During the hot compressive deformation, the strain softening is very apparent in the composites with the whisker orientation angles 0° and 30°, whereas it is not obvious in that with the whisker orientation angle 45°. The composite with the whisker orientation angle 90° shows work hardening phenomena.
LI Qing, HUA Wen-jun, CUI Yan, ZHANG Shao-qing. Fabricating Aluminum Toughed Boron Carbide Composites by Pressureless Infiltration Technology[J]. Journal of Materials Engineering, 2003, 0(4): 17-20.
Cermet composites of high ceramic fraction are made by infiltrating the aluminum(L4) or aluminum alloys(LC4 )and casting aluminum alloy into boron carbide ceramic preforms during a pressureless infiltration process. The flexure strength are from 350 to 600 MPa, and the fracture toughness are from 5 to 9 MPa·m-1/2. The microstructures of the composites are observed by an optical microscope,the transmission electronic microscope and the scanning electron microscope and the phases are analyzed by X ray diffractometer. The results indicate that a well interface connect can be achieved. An reaction zone of Al3BC connect both the aluminum and the ceramic toughly. An connected ceramic frame are formed in the composites and the composites are toughed by the metal.
HAO Wei, LI Yong, LUO Yu-qing. Research and Processing of the Antenna[J]. Journal of Materials Engineering, 2003, 0(4): 21-23,38.
The influences of raw materials and molding process on the structure property and electricity of antenna were studied. The results show that the antenna can be made by chosing proper raw materials and using vacuum bag molding process. The antenna carried on plane has the more advanced properties in our country currently.
ZHANG Jie, FENG Sheng-yu. DC Current-Voltage Characteristics in the Electrical-Thermal Equilibrium State for Conductive Silicone Rubber with Different Resistivity-Tempearture Effects[J]. Journal of Materials Engineering, 2003, 0(4): 24-26,9.
DC current-voltage characteristics in the electrical-thermal equilibrium state for conductive silicone rubber with different resistivity-temperature effects were studied. The results indicate that in certain voltage range the deviation trend of current-voltage relation from Ohm’s law for conductive silicone rubber with different resistivity-temperature effects is different. This is because that self-heating behavior of the conductive silicone rubber results in its different resistivity changing trend.
LIU Yu-yan, WAN Zhi-min, TIAN Zhen-hui. Fatigue Damage Model and Fatigue Life Prediction of Unidirectional Rubber Composites[J]. Journal of Materials Engineering, 2003, 0(4): 27-29,38.
Irreversible thermodynamics and damage mechanics are applied to fatigue damage of rubber composites. Based on a large number of experiments, a suitable thermodynamics potential function is selected and then a nonlinear damage evolution equation of rubber composites and the fatigue life prediction equation of rubber composites is established. The experiment results indicate a reasonable good agreement between the model and the actual data. This shows that it is feasible for the established model to predict fatigue life of rubber composites.
LIANG Jing, SHI Yi-wei. Ultrasonic Inspection of Small Defects in Ceramics and Ceramics Matrix Composites[J]. Journal of Materials Engineering, 2003, 0(4): 30-33.
Some specimens with artificial defects were tested ultrasonically for the investigation of the ultrasonic inspection ability. Longitudinal wave straight beam and leaky rayleigh wave methods were used. The results show the difference of ultrasonic inspection ability between these two methods.
ZHANG Rui, CHENG Yi-fang, FU De-yong. Manual Scan Ultrasonic Feature Imaging Testing of Composite Material[J]. Journal of Materials Engineering, 2003, 0(4): 34-38.
The manual featured-scan ultrasonic imaging system for composite materials is developed. The establishment of full-wave acquisition of ultrasonic testing signal makes the system a full-information processing ability of the waveform features for any testing point. Moreover, various testing methods of feature-scan imaging are established: A-scan and parameter measurement, B scanning, C-scan imaging, phase feature imaging, equivalent feature imaging, half-wavelength ultrasonic chromatography and ultrasonic spectrum analysis. A testing experiment of a carbon fiber composite specimen has been done and the result displays the interior quality status of the specimen accurately.
LU Feng, ZHONG Qun-peng, CAO Chun-xiao. Progress of Galvanic Corrosion between the Graphite Epoxy Composite Materials and Metals[J]. Journal of Materials Engineering, 2003, 0(4): 39-43.
Some recent research progress in the field of galvanic corrosion and control between graphite epoxy composite materials(GECM) and metals was reviewed. The basic characters of GECM, galvanic corrosion behavior of GECM/metal couples and modern surface analysis technique used for galvanic corrosion research were introduced. Some protective methods and galvanic corrosion control theory were discussed as well.
YE Yu-fei, ZHANG Zheng. Application of Pattern Recognition to Failure Analysis[J]. Journal of Materials Engineering, 2003, 0(4): 44-47.
Application of pattern recognition to failure analysis is introduced in this paper. Some principal application fields are generalized. The technical challenges and the potential application are described. The pattern recognition is tried to put into practical failure analysis. It is obvious that application of pattern recognition to failure analysis is very important value to research.
