The foaming behaviour of CaO-SiO_2-Al_2O_3-FeO slag system reduced by graphite at 1500℃ was quantitatively studied with the help of X-ray apparatus. Foaming parameters such as foaming ratio and foaming index were determined. It was found that with increase of the basicity of slags, the foaming ratio increased, however, the foaming index was opposite. In addition, the effects of additives like MgO, Na_2O and CaF_2 on the foaming behaviour were also investigated. The result of dimensional analysis showed that the foaming index(∑) of molten slag was determined by where μ is the viscosity of the slag,σis the surface tension, ρis the density of the slag and g is the acceleration of gravity. (Correspondent: HUANG Zongze, Department of Ferrous Metallurgy, Northeastern University, Shenyang110006)

An analysis for the formation conditions of the massive phase in Al-Fe-V-Si alloy was carried out by RS tests and TEM observations. The results show. the temperature range in which the massive phase occurs in is 1173-1103 K. The mixed structure of massive phase and microcellular will occurs when the cooling rate of the melt (the critical cooling rate) in the above temperature range and the cooling rate after RS starting.And the mixed structure of massive phase and coarse cellular will occurs when during whole RS process.(Correspondent: CHEN Longqing, professor, Department of Material, Zhengzhou Institute of Technology,Zhengzhou 450002)

The alloy of Ni-25at.-% Al was prepared by combustion synthesis with self-propagating way, and the evolution of microstructure in as-prepared specimen along with end-quenching was investigated. It was shown that the synthesizing process went from forming a rich-aluminium solution,then gradually transformed into Ni_3Al product through some transition-reactions, these transition-reactions can produce the more rich-nickel aluminides, and their reacting-rate has the dependence on state and mass-transfer way of reactants. Results also indicated that it is the key mechanism of reaction with higher reacting-rate that the reactants and some transition-phase melted and fast spreaded to the surface of Ni particles. (Correspondent: WANG Xuecheng, Lecture, School of Mat Sci Eng, Xi'an Jiaotong University, Xi'an 710049)

BaCe_(0.95)Y_(0.05)O_(3-α) electrolyte is prepared by solid state reaction. In the temperature range of 450-1000℃, the conductivity is 10~(-3)-10~(-2) S·cm~(-1),the activation energy in air is 0.49 eV, measured by impedance spectroscopy technology. The hydrogen sensors for measureing the hydrogen activity in molten Al alloy is manufactured, using BaCe_(0.95)Y_(0.05)O_(3-α) as solid electrolyte, metal hydride as reference electrode and Mo wire as lead wire. The results showed that the sensor has a high sensitivity and a good stability within the range of experiment temperature.(Correspondent: WANG Changzhen, professor, Faculty of Metallurgical Physical Chemistry, Northeastern University, Shenyang 110006)

The quantitative measurements of the typical low-temperature impact fracture surfaces were made by the method for such an even fracture surface vertically cutting apart into mutual 120°angle. The magnification is found to be dependent significantly on the value of measurement. The magnification selected is quite different upon the zigzaging.R_S, of fracture surface. The corresponding impact value of material may match the roughness.R_S, of the fracture surface measured only with a magnification properly selected. Using the present measuring method and based on the convension of coefficients R_S and R_L, a fair measurement of the fractal dimension, D_S, for fracture surface may be also obtained. The comparison of R_S value, measured by this method, with the derived ones from the relation between R_S vs R_L, deduced by Wright and Soudani, may further confirm the effectiveness of this method. Moreover, a method may be proposed to estimate R_S by the plating thickness of the fracture surface.(Correspondent: LI Xiaowu, Institute of Metal Reasearch, Chinese Academy of Sciences, Shenyeng 110015)

By using the coupling broad distribution function of relaxation activation energy in according with the fluctuation in structure of amorphous alloys, the classical activation energy spectrum model is modified, and four different forms of relaxation function are obtained. The dependence of internal friction on annealing temperature and annealing time is experimentally investigated for amorphouse alloys (Pd_(80)Si_(20) and Ni_(80)P_(20)), the streched exponent function is used to fit the decay law, M(t)= exp(-Ct~β). the dependence of exponent(β) on annealing temperature is discussed. (Correspondent: LIU Junmin, Department of Physcics, Zhongshan University, Guangzhou 510275)

It is found that the microcutting is the primary wear mechanism under low stress impact wear (3.5 J), while the delamination is of the primary one under high stress wear (about 160 J, which is similar to real one). The wear loss under high stress condition is also much more than low stress one. The wear mechanism of high stress wear is greatly affected by microstructures. The duplex of bainite and martensite has high wear resistance under high stress condition. (Correspondent: YANG Yeyuan, lecturer, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084)

Study was made of the experimental and theoretical analyses for inelastic thermo-softening of H62 copper and LY12 aluminum specimens subjected to rapid resistance heating by a large electric current and under constant uniaxial tensile load. It is found that the yield temperature of the specimens increases markedly with heating rates. The effects caused by mechanical and metallurgical properties under rapid heating of metals are also investigated. An extended Johnson-Mehl equation of recrystallization is derived to include the effects of heating rates. A new concept of upper and lower limits of yield temperature is put forward for a metal under various heating rates.(Correspondent: Dr. LIU Zongde, Department of Mechunics, Peking University, Beijing 100871)

The effect of additive Ni on the microstructure and properties of C-B_4C-SiC composite was studied. X-ray diffraction indicates that Ni reacts along the grain boundaries with SiC, B_4C to form liguid Ni_(4.6)Si_2B. Thus the effective sintering may be accelerated and the growth of grain was controlled. Consequently, the density and strength of the composite increase markedly, and the electric resistance decreases a little. On the other hand, when the composite was oxidized, Ni_(4.6)Si_2 B was first oxidized to form the dense 2NiO·B_2O_3 which wrapts up carbon and B_4C particles, and makes them difficult to oxidize. So the oxidation resistance of the composite increases greatly. (Correspondent: HUANG Qizhong, associate prpfessor Institute of Powder Metallurgy Research, Central South University of Technology, Changsha 410083)