GU Jidong. Microbial Corrosion of Metals and Deterioration of Polymeric Materials[J]. Journal of Materials Engineering, 1999, 0(7): 3-7.
Microorganisms including bacteria and fungi play an important role in the corrosion of metals and deterioration of polymeric materials.Under natural conditions, a thin layer of microorganisms may adhere on surfaces forming the socalled biofilm.Microbial colonization on surfaces influences the localized electrochemical characteristics of the metals, resulting in corrosion.Other microbial processes inducing corrosion include microbial exopolymeric materials, microbial hydrogen and organic acids produced by the fungi.Heterotrophic microorganisms utilize polymers either directly or indirectly as a source of carbon and energy, and the consequences are weakening of the polymer structure Both autotrophic and heterotrophic microorganisms are capable of deteriorating concrete and stone through production of inorganic acids and sulfur transformation respectively Prevention of biodeterioration is largely done by incorporation of biocides, but bacteria develop resistance quickly by mutation after exposure.
SHI Zhongliang, GU Mingyuan, ZHANG Di, WU Renjie. The Analysis of Reclamation Mechanism of Discontinuously Reinforced Aluminum Matrix Composites[J]. Journal of Materials Engineering, 1999, 0(7): 8-11.
The reclamation mechanisms and their microstructures and interfacial reactions characteristics between SiCp and Al2O3 reinforced as-cast and deformed aluminum matrix composites have been analyzed. It has been put forward about the request of their reclamation.
CUI Chunxiang, SHEN Yutian, MENG Fanbin, WU Renjie. Measurement of Reinforcement Volume Fraction for In-situ TiCAlN/Al Composite[J]. Journal of Materials Engineering, 1999, 0(7): 12-14.
Based on the characteristics that aluminum matrix is easy corroded by NaOH water solution,but TiC and AlN ceramic particles with a high chemical steadiness are not corroded in same condition,the volume fraction of TiC and AlN ceramic particles in-insitu composite has been measured quantitatively by the corrosion method of 10% NaOH water solution. It is proved that this method of volume fraction measurement is effective and simple for the in-situ MMCs with two kinds of reinforcements in the matrix of the composite, so the quantitative measurement of reinforcement volume fraction is considered to serve a series of firm bases of data for the study on the relationship between microstructure and mechanical properties of composite.
ZHU Minggang, WU Hongyan, KONG Lingyi, CHANG Hong. Preparation of Compound Planting Body of Multilayer Hyperfine HA Coat on the Ti Base Surface[J]. Journal of Materials Engineering, 1999, 0(7): 15-23.
In the article,tachnological requirements of repeatly coat-sintering HA-Ti compound planting body with Sol-Gel method have been made to improve the purity, crystallinity and nanoconstruction of multilayer hyperfine HA coat powder,make the coat and basilar mix up with each other composition to reach an even molecular level and form a firm chemical transition coat on the basilar interface.
FENG Yujun, JING Xiaotian, LOU Bingzhe, QI Xiaofang. The Research for the Phase Transtion of Stretching Polyvinylidene Fluoride Film[J]. Journal of Materials Engineering, 1999, 0(7): 18-31.
This paper concentrated on the microstructure changes in uniaxial stretching film of polyvinylidene fluoride. The studying results show that in undrawn film the crystal phase exists with sperulites.The stretching transformed from α-sperical crystal into β-lamellar crystal,and the transformed volume fractionis increased as the stretching ratios raised.On the condition of the casting film stretched at air temperature,the α-crystal could be completely transformed into β-crystal while the stretching ratio is stretched to D≥42.
MIN Guanghui, YU Huashun, CHEN Xichen. Behavior of Particle at Solid-Liquid Interfacein Solidification[J]. Journal of Materials Engineering, 1999, 0(7): 21-23.
The energy condition of engulfing/rejection of particle by advancing solidliquid interface was discussed.There is a transition zone between engulfing and rejection,and it is determined with interface energy of solid-liquid.The dynamic condition was also obtained on the bases of particle motion related to the advancing interface and energy condition. The conclusions are in accord with experiment results done by others.
ZHANG Jinzhi, XU Zushun, CHENG Shiyuan, CHEN Zhengguo, WANG Zhiqiang. Study on Particle and Emulsion Properties of Soap-freeCationic Polymer Emulsion[J]. Journal of Materials Engineering, 1999, 0(7): 24-26.
Soap-free cationic emulsion copolymerization of styrene(St)and butyl acrylate(BA)in the presence of cationic comonomer N,N-dimethyl,N-butyl,N(3-methacrylamidino)propyl ammonium bromide (DBMPA) was carried out using 2,2'azobis(isobutyramidine hydrochloride)(AIBA) as initiator The size (Dw),number(Np),and the surface properties of latex particles were characterized by means of PCS particle size analysizer,ioni-cexchange conductimetric titration respectively.The stability of latex and the property of film were characterized using surface tension analysizer and DSC respectively.
ZHANG Shaojun, SUN Lianke, CHENG Ruiping, WANG Qingpu, ZHAO Shengzhi. High Efficiency Laser Crystal Nd:S-FAP[J]. Journal of Materials Engineering, 1999, 0(7): 27-28,46.
High efficiency,low threshold laser crystal Nd3+ doped Sr5(PO4)3F,or Nd:S-FAP has been reported in this paper.Using a tunable dye-laser(575.0nm) and diode laser (LD) as pump source, we have realized the performance of total polarized Nd:S-FAP laser at 1059.4nm and intracavity doubling Nd:S-FAP/KTP laser at 532.7nm.The lowest threshold and the highest slope efficiency are 25mJ and 49% for the Nd:S-FAP laser pumped by dyelaser;the threshold and the slope efficiency are 9mW and 373% for the Nd:S-FAP laser pumped by LD;the threshold and the lightlight efficiency are 12.1mW and 95% for the intracavity doubling Nd:S-FAP/KTP laser pumped by LD, respectively.
YAO Chengzhao, FENG Zhihai, XU Bin. A Study of Whole Stitch Relay on Mould Processing Technologyof Composites Fabric Reinforcements[J]. Journal of Materials Engineering, 1999, 0(7): 29-31.
Whole stitch rely on mould process method is a newly developed technology for textile structure composites fabric reinforcements.The fabric whole stitch process includes stitch mould design, single layer cloth selection, stitch thread and needle preparation, fabric laying technology design, fabric whole stitch process etc.The composites components made by this technology have been put into practical.This technology is being proved that fabric whole stitch rely on mould process technology to manufacture through thickness fabric reinforcements for advanced composites is efficient.
LI Yimin, QU Xuanhui, HUANG Baiyun. Evaluation of Rheological Properties of Metal InjectionMolding Feedstocks[J]. Journal of Materials Engineering, 1999, 0(7): 32-35.
The rheological properties of metal injection molding (MIM) feedstocks were analyzed theoretically.It was found that the evaluation system of the rheological properties of MIM feedstocks included the feedstock viscosities and its sensitivity to the shear rate and the temperature, which could be described as a general rheological index for MIM feedstocks The rheological properties of several kinds of Fe-Ni and W-Ni-Fe MIM feedstocks with different binder composition were evaluated using the general rheological index for MIM feedstocks.
YANG Chun, LUO Fei, SHEN Chao, LI Hongyun, ZHANG Baoyan. Insitu Cure Monitoring of Fabrication of Epoxy ResinComposites with a Novel Fiber-optic Sensor[J]. Journal of Materials Engineering, 1999, 0(7): 36-39.
A cost-effective approach is supposed to in-situ monitor the fabrication of epoxy resin composites with a fibe-roptic sensor. A fibero-ptic evanescent wave refractive index sensor is made by removing a short region of the cladding of a low refractive step index optical fiber. The sensor is used to in-situ monitor the viscosity variation and cure process during the fabrication. As the sensor respones the integrated effects along the sensing region, the influences of the defects in the resin such as voids and impurity can be reduced on a large extent. In order to facilitate the operation, a probe configuration is made by depositing a retroreflectic film on the distal end of the optic fiber near the sensing region. Experiments have been performed on the epoxy prepreg hot pressing to test the feasibility of the supposed approach.
LIU Shizhong, LI Jiarong, TANG Dingzhong, ZHONG Zhengang. Numerical Simulation of Directional Solidification Process of Single Crystal Superalloys[J]. Journal of Materials Engineering, 1999, 0(7): 40-42.
The thermal fields of the directional solidification of single crystal superalloys have been measured at various withdrawal rates.The entity model of a simulated system has been built and thermal fields have been calculated with ProCAST software.The results show that the discrepancy between the measured temperature data and the calculated temperature data is lower than 5% at three different withdrawal rates above 1000℃, the curvatures of the liquid lines are increasing with withdrawal rates increment.The numerical simulation of the directional solidification of single crystal superalloys can provide an available tool for optimizing solidification process.
WANG Shuhe, GUO Jianting, LAI Wanhui, TAN Minghui, LI Hui, YIN Weimin. Effect of Minor Y on Microstructure and Mechanical Properties of a Cast Ni50Al20Fe30 Alloy[J]. Journal of Materials Engineering, 1999, 0(7): 43-46.
The effect of Y contents on microstructure and mechanical properties of a cast Ni50Al20Fe30alloy has been investigated The results show that minor Y addion can improve the strength and the ductility of the Ni50Al20Fe30alloy The 005wt%01 wt% Y content is optimal addtion in the alloy The minor Y can influence the eutectic zone and morphology in the alloy When doping with 0.1wt% Y content, the alloy mainly constituted of fine eutictic microstructure of (NiAl)and phase This microstructure is of benefit to ductility at room temperature.
YIN Keqin. Ways for Improving Purity of Cast Superalloy and Its Precision Casting Component[J]. Journal of Materials Engineering, 1999, 0(7): 47-49.
At present,the purity of the cast superalloy and its precision casting component is an important technology problem during the process of producing alloy and precision casting component in our country. It has been paid great attention to by metallurgist since it not only affects the level of the alloys property and the stability, but also the quality and the qualified rate of the components The factors including raw materials, metallurgy process, impurity and gases distributed in the cast ingot or the component are discussed in detail in this paper. In order to improve the metallurgical quality and the qualified rate of the cast component, the technical requirement and the ways to reach the requirement have been also proposed.
