LIU Guoquan Department of Materials Science and Engineering
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University of Science and Technology Beijing
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100083
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China.
材料科学技术（英）
Quantitative analysis of populations having a geometric structure,which has developed into a special scientific subject called microstructology or stereology,is of great importance to the characterization and evaluation of microstructures and their evolution in various processes.This paper, besides a brief discussion on those topics such as the recent developments of computer assisted image analysis,mathematical morphology,and fractal analysis,will mainly focus on the scope,fundamen- tals,present status,and perspectives of classical stereology.Several case examples of its application to materials science will also be given.
关键词:
stereology
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HU Benfu University of Science and Technology Beijing
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Beijing
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ChinaTAKAHASHI Heishichiro
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ITOH Hisatoshi
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TAKEYAMA Taro Hokkaido University
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Sapporo
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060
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Japan Associate Professor
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Dept of Materials Science and Engineering
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University of Science and Technology Beijing
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Beijing 100083
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China
金属学报(英文版)
The behavior of void swelling and segregation in Fe-15Cr-xMn alloys and an alloy con- taining small amount of W and V was investigated by electron-irradiation.The compositional analysis in the irradiated regions including grain boundaries was performed.The resultdts show that there are many common features of irradiuation tehavior in the Fe-Cr-Mn and Fe-Cr-Ni systems while there are some significant differences,In the Fe-Cr-Mn alloy sys- tems void swelling was rematrkably suppressed and at the same time the radiation-induced segregation was also retarded,furthermore,the segregation was strongly retarded in an Fe-15Cr-15Mn alloy containing small amount of W and V.The results also show that Ni re- placed by Mn does not in general confer immunity from either swelling or phase instabilities. The phase instability is due to the different diffusion behavior of Ni and Mn in reponse to the operation of the inverse-Kirkendall effecr.Fe segregates to the microstructural sinks in the Fe-Cr-Mn alloys.The segregation of Fe often leads to the formation of ferrite.This fact is beneficial to reducing the swelling rate and segregation on the grain boundaries.
关键词:
electron irradiation
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QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
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Beijing
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China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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J.M Hu
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J.X. Wu
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H.M Meng
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YR. Zhu
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D.B. Sun and D.J. Yang(Beijing Corrosion and Protection Center
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Open Laboratory of Corrosion
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Erosion and Surface Technology
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University of Science and Technology Beijing
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Beijing 100083
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China)
金属学报(英文版)
Titanium based IrO2 +Ta2O5 oxide anodes with different compositions and pyrolysis temperatures were prepared by termodecompoisition method. By using X-ray diffraction (XRD), the structure and texture coefficient of the coatings, TC(hkl), of IrO2 rutile crystal have been tested. It showed that, the crystallization processes of IrO2 and Ta2O5 in xIrO2 +(100-x) Ta2 O5 (x is in mol%) films affected and confined each other.In the mixed system, IrO2 rutile phase existed as a solid solution with Ta, and attained the maximum solubility when x=70mol%, i.e. for the coating of 70% IrO2 +Ta2O5.For the coatings of low iridium content or at low preparing tem pemture, (110) and (101) pwtered orientations were dominant. However, preferred growth of IrO2 weakened with increasing either iridium content or temperature. Three typical surface morphologies were observed by using scanning electron tnicroscopy(SEM). The crystallite size of the mixed oxide coatings were finest for the the film of 70%IrO2 +30%Ta2O5,and decreased with the pyrolysis tempemture. As the results of the finest crystallite segregating on sudece and the maxitnum solid solubility of Ir and Ta component in deposits, the coatings with the composition of 70%IrO2 +Ta2O5 prepared at 450℃ presented the mdrimutn electrocatalgtic activitg for O2 evolution in 0. 5M H2SO4 solution.UP to 550℃, Ti base suffered to oxidation resulting in decreasing anode conductivity,therefore, coatings performed a low activity.
关键词:
titanium based coating anode
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WANG Yanbin
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WANG Anrong
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CHU Wuyang
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XIAO Jimei University of Science and Technology Beijing
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Beijing
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China associate professor
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Department of Materials Physics
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University of Science and Technology Beijing
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Beijing 100083
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China
金属学报(英文版)
The formation and aggravation of hydrogen damage in Fe-3 wt-% Si alloy during cathodic charging Were studied by means of Lange transmission X-ray topography.Results showed that hydrogen damage did not form in the specimens charged in 0.5 mol/L H_2S0_4 so- lution without poison,and occurred with addition of 250 mg/L As_2O_3 even at very low charge current density.As charging at a certain current density,the size of the damage may enlarge up to a limit yet no more by prolonged time.The damage size increased with increase of charging current density,but not so apparent at high current density. An external tensile stress could promote the formation of hydrogen damage obviously. It seems that for charging in H_2SO_4 solution containing poison,the drop of hydrogen permeation curve against time prolongation is due to the formation of hydrogen damages.
关键词:
hydrogen embrittlement
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DENG Yongrui University of Science and Technology Beijing
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Beijing
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ChinaG.S.Ansell Colorado School of Mines
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Golden
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CO 80401
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USA) Associate professor
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Department of Materials Science and Engineering
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University of Science and Technology Beijing
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Beijing 100083
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China.
金属学报(英文版)
The growth of thermoelastic martensite in a Cu-29% Zn-3% Al alloy has been investigated experimentally and theoretically.Metallographie observations showed that the growth oc- cured thermoelastically,i.e.reversibly,in the radial direction as well as in the thickening di- rection.This is not consistent with the theories of Conhen and some others.A model has been suggested to explain the thermoelasticity of the growth.The basic idea is:the elastic strain distribution is highly heterogeneous and the growth is controlled by the local elastic strain en- ergy at the growth frontier area.The calculated results from the model based on Eshelby's theory are consistent with the observations.
关键词:
thermoelasticity
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DONG Hongbiao JI Yongyi ZHU Jun LU Shuzu ZHONG Xueyou University of Science and Technology
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Beijing
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ChinaLI Jianguo Northwestern Polytechnical University
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Xi'an
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China DONG Hongbiao
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lecturer
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Department of Metallurgy
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University of Science and Technology Beijing
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Beijing 100083
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China
金属学报(英文版)
In situ eutectic Al_(11)La_3/Al composite material with regular arrangement was prepared by zone melt liquid metal cooling directionally solidification under conditions of high temperature gradient G=700K/cm and growth rate R=6.0-20.0μm/s.Superpose diffraction pat- tern of Al_(11)La_3/Al composite shows that the preferred growth direction is[100]Al// [33]Al_(11)La_3,and the habit plane is(002)Al//(116)Al_(11)La_3.A low density(103)twin is ob- served in Al_(11)La_3 and the growth of(103)twin induces to branching to change the interlamellar spacing.
关键词:
eutectic solidification
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JIANG Guang
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WU Yinshun
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LI Jiuqing
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LIU Haiping University of Science and Technology Beijing
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Beijing
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China Department of Surface Sciences and Corrosion Engineering
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University of Science and Technology Beijing
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Beijing 100083
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China
金属学报(英文版)
Observation was carried out of the structure of sulphuric,oxalic or phosphoric film on Al after treatment of reanodizing and electrolytic depositing lubricant in (NH_4)_2MoS_4 solution,as well as of the deposited products by means of EMPA,TEM and energy spectro-scopic analysis.The deposited products are mixture of compounds of S and Mo rather than single MoS_2 and most of them dcposited near the surface layer of the film.Some regular long pores without barrier layer occurred in the film,but the regular fine channels without relation to the structural element parameters of original anodized film were found in the thickened barrier layer of phosphoric film.Sulphur may be remained as Mo sulphide in the film during heating under Ar protective environment.
关键词:
Al
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