Wang Guangsheng. Present Situation and Development Trends of Heat Treatment in Nitrogen Based Atmosphere[J]. Journal of Materials Engineering, 1997, 0(2): 3-6,48.
Technical achievements and application situation of heat treatment in nitrogen based atmosphere are presented,and its application prospect in aviation industry is reviewed.
Wang Ziwang, Chu Shuangjie, Wang Haowei, Wu Renjie. Determination of Residual Stresses in Metal Matrix Composites[J]. Journal of Materials Engineering, 1997, 0(2): 7-9.
This study analysed the formation mechanism and characterization of the stresses with the common methods. X-ray diffraction method takes the advantage of simplicity and economy,but its penetrating ability is so limitive that it is just able to measure the state of resid-ual stresses at the surfaces of a body.Nentron diffraction method is able to penetrate deeper than X-ray and an internal stress is indeed measured by this approach,while diffraction volumes are required and only bulk average stress are determined.X-ray energy dispersive diffration method, offers both the good penetration and a high spatial resolution to resolve the residual stress gravients. It is the efficient approach.
Zhou Shaorong, Bai Shihong, Qiao Shengru, Sun Xiaoyan. Mesophase Pitch for Carbon Matrix of Carbon/Carbon Composites[J]. Journal of Materials Engineering, 1997, 0(2): 10-12.
Mesophase pitch exhibits high carbon yield,high density,minimal density change and easy graphitization,so it is the ideal precursor for the carbon matrix of carbon/carbon (C/C) composites.Based on the process technology of C/C composites,the main characteristics of mesophase pitch for C/C composites are summarized in this paper,such as flowability,stabi-lization on carbonization,interface in C/C copmosites and microstructure of the mesophase pitch matrix,as well as effects on composites properties.
Liu Haozhe, Wang Aimin, Ding Bingzhe, Hu Zhuangqi, Peng Hongying. In Situ Synthesis of Al3Ni Whiskers Reinforced Al Matrix Composites U nder High Pressure[J]. Journal of Materials Engineering, 1997, 0(2): 13-14,35.
The Al3Ni whiskers reinforced Al matrix composites were successfully in situ synthesized under high pressure within 1～6GPa.The sizes of Al3Ni whiskers are fine,and uni-formly distributed in these densified composites.The influence of high pressure on the size and structure of Al3Ni whiskers are disccused.
Pei Zhibin, Tian Changsheng, Zhao Xinwei. A Study of the Preparation of(Pb, La) TiO3 Ferroelectrics Thin Films by Sol-gel Process[J]. Journal of Materials Engineering, 1997, 0(2): 15-17,45.
The gelation mechanism,stability of sol-gel precursors and multilayer spinning technology were studied.
Wang Xiao, Xu Jiarui, Zeng Hanmin, Lu Mei. Stability of PVA Suspensions for the Preparation of Short GF/PP Composites with Suspension Impregnation[J]. Journal of Materials Engineering, 1997, 0(2): 18-21,32.
A new process of suspension impregnation for the preparation of short glass fiber reinforced polypropylene composites has been developed.The influences of ingredients of the suspensions in which PVA is used as a stabilizing agent on the stability of the suspensions are investigated.The functional relationship between the concentrations of the stabilizing agent and the separating time of the suspensions is given.
Liang Zicai, Jiang Bo, Kang Shumin. Mechanical Relaxation and Structure Changes in Nylon 11[J]. Journal of Materials Engineering, 1997, 0(2): 26-29.
By using dynamic mechanical measurements in the temperature range from -180℃ to 180℃,three relaxation peaks,labeledα,β andγ at 76,-52 and-140℃ respectively, were observed in the dynamic mechanical temperature spectra of nylon11films.The main transition α peak is due to the motion of chain segments in the amorphous regions of nylon 11.The strongγ relaxation peak is believed to involve the motion of the longer (-CH2-) groups between two amide groups.The β relaxalion peak which is very weak in a dry sample is highly intensified by small moisture content.The elastic modulus of nylon 11is increased by drowing and annealing.The influence of the crystallinity of nylon 11on the mechanical properties will be discussed.
Wu Zhengan, Gu Mingyuan, Zhang Guoding. Oxidization Characteristics of Boron Carbide[J]. Journal of Materials Engineering, 1997, 0(2): 30-32.
The oxidization characteristics of boron carbide during sintering at 400～800℃ in air were investigated.The phase structure and surface morphology of oxidized boron carbide were analyzed and observed using X-ray diffraction and scanning electron microscope,respectively. The results show that the oxidation of boron carbide begins at about 600℃,after oxidization, the boron cabide partially transformed into amorphous boron oxide,the oxidization is a thermally activated process,the activation energy Q=17.17kJ/mol.
Zhang Jun. Improvement on Structure for the Pattern Die of a Complex Aero-Engine Hollow Blade[J]. Journal of Materials Engineering, 1997, 0(2): 33-35.
Through analysing the shrinkage of the ceramic cores,this paper introduces a new mechanism for the pattern die of a complex hollow turbine blade,which can adjust the position of ceramic core holded in the die easily and accurtely.Carrying on all advances of the old die,the new pattern die can be operated simply,correctly adjust the thickness of the wall of patterns and increases the qualified rate of the thickness of the wall of patterns and producing efficience.
Xu Jinsong. Application of Coatings for Gas Turbine Blades and Vanes[J]. Journal of Materials Engineering, 1997, 0(2): 36-37.
The properties of coatings for hot corroxion protection of gas turbines operating in a lower grade diesel oil in foreign countries was briefly introduced. The best protective effects of rich-Cr MCrAlX (M=Ni,Co,NiCo,X=Y,Si,Hf) coating was defined.
A. G. Bratukhin, B. S. Denisov, V. S. Sotnikov. Technological Problems of 1420 Aluminum-Lithium Alloy Aircraft Structure with Use of Welding[J]. Journal of Materials Engineering, 1997, 0(2): 38-41.
Some technological problems of 1420 Al-Li alloy aircraft structure with use of welding,such as welding methods,welding wire,welding parameters and its influence on mechanical properties of structure,are reviewed.
Jiang Yijun, Liu Weiping, Zhai Quansheng. A Study of Composite Scarf Bonding Repair in CFRP Monolithic Structure[J]. Journal of Materials Engineering, 1997, 0(2): 42-45.
This paper describes the repair methods of composite stiffened panels with the damage of penetration and non penetration.The repair material 3216/T300 is a kind of epoxy resin system which can be cured at 120℃,and in the case of field repair,it has the good synthetical properties.The research results show that whether the damage of composite stiffened panel is penetrative or non penetrative,the static strength of structure can be fulfilled with the 3261/T300 prepreg and the SY-24 adhensive film.
Hou Shue, Ma Zongli. Crack Analysis of Inside Sphere of Liquid Oxygen Vessel[J]. Journal of Materials Engineering, 1997, 0(2): 46-48.
The crack of inside sphere of liquid oxygen ressel has been analyzed by using OM,EPMA and SEM. It has found that the layer of cuprum plating near weld bead and heat affected zone was not removed complettly by grinding and/or the area was removed too small to melt layer of cuprum.the cuprum melts osmose along the capillary in matrix grain boundaries. As a resuld,Once the welding stress is acted upon,the cuprum embritteement will be produced.
Liu Dongsheng. Research &Application of High Stress Endurance Property of Titanium Alloys[J]. Journal of Materials Engineering, 1997, 0(2): 49-49.
The research of high stress endurance property of titanium alloy,and application for Aeronautical department standard and national military standard were described.
