A nanocrystalline Cu30Al70 alloy catalyst precursor was produced by mechanically milling the conventional Raney copper catalyst precursor Cu30Al70 which is widly used in industry. The weight ratio of balls to sample and the milling time have significant effects on the grain size of the Cu30Al70 alloy. The mean grain size of the CuAl2 phase in the Cu30Al70 alloy is about 12 nm after 20 h ball milling. The element Cu is homogeneously distributed in the ball-milled nanocrystalline Cu30Al70 alloy. The activity of the ball-milled Raney Cu is much higher than that of the conventional Raney Cu in hydrogenation of xylose. Correspondent: SUN Li, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015

3-dimensional fluid flow and mixing characteristics in gas-stirred ladles were studied by using the authors'code. The effects of various operating conditions on fluid patterns and mixing in gas-mstirred ladles were investigated. An empirical relationship for mixing time and an optimum location for the nozzle in the ladle were proposed. The predicted results are in good quantitative agreements with the measured ones. Correspondent: ZHU Miaoyong, postdoctoral, Deportment of Ferrous Metallurgy, Northeastern University.Shenyang 110006

The microstructure changes in the nanocrystalline soft magnetic material of FeZrB(Cu) alloys with different temperatures of heat treatment and dynamic heating-up processes have been investigated by using TEM and EDAX. It has been found that there appears appreciable phase separation before crystallization. In amorphous phase there are Zr-rich and Fe-rich regions. The Zr-rich phase has a very important effect on precipitation and stability of bcc Fe phase, and the obvious precipitation of α-Zr phase indictates the beginning of instable growth for bcc Fe phase. It has been confirmed that the phase separation of FeZrB(Cu) alloys is a spinodal decomposition process. Correspondent. LING Gang, postdoctor, Box 61, Beijing Agricultural Engineering University, Beijing 100083

Structure and stability of the passive films on 2205 and 316L stainless steels in the NaCl solution media, 0.5 and 1.0 mol/L, were studied by using the potentiostatic-galvanostatic (P-G) transient technique. A multiple layer structure of the passive films is revealed on both steels. The action model and breakdown mechanism were suggested on the discussion of the Cl- behaviour against growth and breakdown of the passive films on the steels.The polarized potential dependence on the electrochemical parameters may be determined by P-G response curves. The corrosion resistance to NaCl media of 2205 diphase steel is much superior to that of 316L steel. Furthermore. A preliminary discussion of effect of metallographical structure of 2205 diphase steel on the stability and pitting resistance of passive film was made.Correspondent: SONG Shizhe, professor, Department of Materials Science and Engineering, Tianjin University, Tianjin, 300072

A large extent of grains refinement in the Fe-28Al-5Cr (at.-%) alloy may be performed by hot-rolling at temperature over recrystallization. The hot-rolling deformation reduction should be controlled to prevent cracking during hot-rolling. The warm-rolling deformation reduction at temperature below recrystallization is much influential to the room temperature mechanical properties of the alloy. SEM observation shows that some ductile dimples occur on the fracture surface of grains in the strips, i.e., the Fe3Al based alloy seems to be of noninherent brittleness.Correspondent: YU Xingquan, lecturer, Department of Materials Science and Engineering, Southeast University, Nanjing ,210096.

The separated eutectic for nearly 20 kinds of simple and complex eutectic alloys was investigated. It shows that most metal-nonmetal eutectic and a part of metal-intemietallic compound eutectic were separated by electromagnetic stirring. The eutectic in which one of its component phases possesses an entropy of solution over 23 J/(mol. K) shows noted separation.Correspondent. JIN Junze, professor, The Engineering Research Center of Foundry, Dalian University of Technology, Dalian 116023

The electrochemical properties of RE(NiCoMnTi)5 hydrogen storage alloys with different compositions of rare earth components (RE= La1-x-y-zCexNdyPrz) were systematically examined. The results showed that all La, Ce, Nd and Pr had an intense effect on the electrode performance. To show synthetic effect of rare earth elements, isographs of alloy electrodes vs quasi-ternary rare earth composition of the alloys were accomplished by first dividing the component elements into two groups and fixing definite ratios between the groups and then using a computer program for engineering graphics. The isographs were used to evaluate the properties of the multicomponent RE(NiCoMnTi)5 hydrogen storage alloys studied.Correspondent: JIANG Jianjun, lecturer, Department of Automotive Engineering, Huazhong Univervity of Science and Technology, Wuhan 430074

After constant temperature superplastic welding. The fractures in welded joint of 40Cr-40Cr and 40Cr-T10 steel have been analysed and the model of joint composition has been suggested, which includes metallurgical jointing area, mechanical jointing area and microcavity. It seems to be an approach to improving the technique of the superplastic welding and inspecting quality of joint.Correspondent:YANG Yunlin, associate professor, Department of Materials Engineering, Luoyang Institute of Technology, Luoyang 471039