QU Heng-lei, ZHOU Lian, WEI Hai-rong. Two Influence Factors on Oxidation of TiAl[J]. Journal of Materials Engineering, 2000, 0(1): 3-6.
Effects of surface roughness and atmosphere flow ability on 900 ℃ interrupted oxidation behavior of five kinds of TiAl-based alloys(Ti-50Al,Ti-48Al,Ti-52Al,Ti-48Al-1Cr,and Ti-48Al-4Cr) in as-cast state were investigated by TGA method.The results show that oxidation extent of all TiAl-based alloys becomes heavier as surface roughness increases from Ra1.6 to Ra12.5.Comparing with static air (ν=0mm•s-1),air flowing (ν=1mm•s-1) also causes the degradation of oxidation resistance of TiAl-based alloys.The former result is due to the oxidation-caused internal stresses and inevitable calculation error,the later one is induced by the difference of supplementation of oxygen in atmosphere,but both of them are related to fragmentation oxidation period.
LI Zhi, QU Jing-xin, WU Zhong-xing, ZHOU Ping-an, SHAO He-sheng. Study on Microstructure and High Temperature Wear Characteristics of a Vacuum Melting Ni-base Alloy Coating[J]. Journal of Materials Engineering, 2000, 0(1): 7-12.
Microstructure and high temperature wear characteristics of a vacuum melting Ni-base alloy coating have been studied.The results indicate that the main separating phases include borides,carbides and silicides,of which the borides and carbides are dispersion strengthening phases while the silicides mainly improve technological properties of the vacuum melting process.The main mode of wear is micro-plowing and because of comparatively high hardness at high temperature,the Ni-base alloy coating has better wear-resistant properties than 3Cr2W8V steel which becomes drastically softening as the temperature is beyond 500℃.During wear process oxide layer formed and covered the wear surface,which protected the wear surface and decrease the wear.
GUO Jing-jie, LIU Yuan, SU Yan-qing, REN zhi-jiang, JIA Jun. Optimum Design of Processing Parameters during ISM Process of Ti-5Al-2.5Sn[J]. Journal of Materials Engineering, 2000, 0(1): 13-16,30.
Based on the direct finite difference method,a numerical model for simulating the temperature fields in the charge during Induction Skull Melting (ISM) process has been developed.By use of the simulation program,the changes of the temperature fields in the charge of Ti-5Al-2.5Sn have been calculated under various melting conditions.An appropriate feeding way of the melting power has been presented.The influences of the charge weight and melting power on the ultimate temperature and weight fraction of the liquid melt have been studied.The processing parameters which are optimized would be the role of theoretical instruction to the practical melting processes.
LIU Shuang-mei, LIU Dao-xin, FAN Guo-fu. Investigation on Galvanic Corrosion Susceptibility of Heat-Resistant Stainless Steel Contacted with TA7 Alloy[J]. Journal of Materials Engineering, 2000, 0(1): 17-19,30.
The galvanic corrosion susceptibility (GCS) of heat-resistant stainless steels 1Cr11Ni2W2MoV and Cr17Ni2 contacted with titanium alloy TA7 in 3 5% NaCl solution was evaluated according to aeronautic criterion.The influence of surface conditions on GCS behavior and the GCS mechanism were investigated.It is found that the GCS datum reported in literature is not useful for guiding the compatibility design of heat-resistant stainless steels and titanium alloy used in compressor.The galvanic current density parameter adopted in aeronautic criterion can not be used to evaluate GCS of passivation materials.
SHAO Xin, WANG Hong-gang, MAO Shao-lan, GAO Jin-tang. Study on Wear Mechanisms of Modified Bismaleimide Matrix Solid Lubrication Film with High Temperature Resistance[J]. Journal of Materials Engineering, 2000, 0(1): 20-23.
The tribological properties of the bonded solid lubrication coatings as modified bismaleimide matrix with high temperature resistance were examined using a pin-disk tester under different temperature in air.The tribological test results demonstrate that the coating not only has good tribological property but also can be used for a long time in the range of room temperature to 250℃.DSC,SEM and XPS had been utilized to explore the wear mechanisms.Analyses of worn surface indicates that the transfer of lubricating film is not good under the ambient temperature whereas it is easy to form the complete transfer film under 200℃.
ZHU Yong-fa, WANG Li, YAO Wen-qing, CAO Li-li. The Study of Interface Diffusion and Reaction between Cr and Diamond Deposited by Magnetron Sputtering Technigue[J]. Journal of Materials Engineering, 2000, 0(1): 24-26,37.
A Cr layer with thickness of 150nm was successfully deposited on the surface of diamond particles using DC magnetron sputtering technique.The interface diffusion and reaction between Cr layer and diamond substrate have been studied using AES depth profile and line shape analyses.The results show that interface diffusion and reaction take place during the deposition of Cr layer.The Cr atoms diffuse into diamond substrate,and react with carbon atom in diamond to form carbide on the interface.The interface diffusion and reaction result from the impact of Cr atoms which keep an energy of 3~4eV.The interface diffusion and reaction can be promoted significantly by raising the sputtering power.
BI Gang, WANG Hao-wei, WU Ren-jie, SHI Zhong-liang, ZHANG Di. Reactivity of Aluminum Borate Whisker Reinforced ZL109Al Alloy[J]. Journal of Materials Engineering, 2000, 0(1): 27-30.
Al2O32B2O3 whisker reinforced ZL109 alloy were fabricated by squeeze casting technique.By means of DSC,XRD and SEM analysis,the reactivity between 9Al2O32B2O3 whisker and the ZL109Al matrix was studied.The results show that the alloying elements and the processing temperature have strongly influence on the occurrence of the interfacial reaction.The magnesium is one of main reasons that cause the interfacial reaction,aluminum can react with AlBOw,oxygen promotes the interfacial reaction,and Cu,Ni don't take part in the interfacial reaction.Temperature is another of main reasons that cause the interfacial reaction:if the temperature is higher than 690℃,both Mg and Al react with the 9Al2O32B2O3 whisker.If the temperature ranges from 449℃ to 690℃,only Mg reacts with the whisker.
HUANG Yue-shan, LI Wen-fang, MENG Ji-long, ZENG Mei-qin, HE Tie-jun. The Effect of Aging on Sliding Wear Properties of Al2O3-SiO2(sf)/ZL109 Composite[J]. Journal of Materials Engineering, 2000, 0(1): 31-32,37.
The aging behaviors and sliding wear properties of Al2O3-SiO2(sf)/ZL109 composite were studied in this paper.Aging treatment can improve the hardness and strength of the composite,reduce the adhesion wear volume,and decrease the coefficient of friction.So the wear resistance properties of the composite can be improved.Alumna-silica short fibers in the composite can make a large acceleration effect on the process of the aging.With the fibers volume fraction increasing best wear resistance properties of the composite come out in a lower aging temperature and a shorter aging time.
CHANG Bao-hua, SHI Yao-wu, LU Liang-qing. Effect of Spot Pitch on Stress and Strain Distribution and Strength of Weldbonded Joints[J]. Journal of Materials Engineering, 2000, 0(1): 33-37.
Numerical and experimental methods were employed to investigate the effect of the spot pitch on the stress and strain distribution and the joint strength.Results show that when improving spot pitch in weld bonded joints with high elastic modulus adhesives,stresses in weld spot zone are decreased while stresses and strains at edges of overlap region are increased slightly.For the joints with low elastic modulus adhesives,both stress concentration degree at the weld spot and the shear strain at edges of overlap region are increased with the spot pitch increasing.Therefore,fracture strengths of the adhesive layers in both types of joints would decreased with the increase of the spot pitch.Experimental results are in good agreement with that from computations.
LI Pei-yong, DAI Sheng-long, CHAI Shi-chang, LI Yu-ren. Recent Developments in New High-Damping Metallic Materials[J]. Journal of Materials Engineering, 2000, 0(1): 38-41.
In this paper,the recent developments in research routes,preparing methods,properties,etc for new high-damping metallic materials were reviewed.The problems existing in the present research and the research directions for high damping metallic materials were pointed out.Especially,the prospects of the research and applications for the high-damping metal/metal composite materials in the future were outlined.
ZHONG Zhi-gang, LI Dong-sheng. Development of Clutch Plate for Heavy Vehicles[J]. Journal of Materials Engineering, 2000, 0(1): 42-43.
Chemical composition,properties,and fabrication processing of the domestic ceramet friction piece for the of heavy vehicles are reviewed.A comparison between the friction piece and external products is made with respect to friction and wear performance.It is found that the friction piece is a match for external product.
QU Shao-bo, YANG Zu-pei, GAO Feng, TIAN Chang-sheng. The Theory and Its Recent Development of Order-disorder Transformation for Relaxor Ferroelectrics[J]. Journal of Materials Engineering, 2000, 0(1): 44-48.
This paper outlines and reviews the theory and its progress in order-disorder transformation for relaxor ferroelectrics,and also prospects the future of the theory briefly.
