Internal friction of Al bicrystals with mis-orientation angles 60° and 129.5°was measured with forced-vibration method. Internal friction peaks vs temperature were ob-served around 200℃ (frequency 1Hz) with an activation energy of about 0.88 eV. Preliminarydiscussions were made on the mechanism of this internal friction peak.

The dislocations in MoS_2 with layer structure have been observed by means ofTEM. On the basal plane, dislocations and dislocation networks dissociate into partial dislo-cations and partial dislocation networks. The Burgers vectors of the dislocations are determined by diffraction contrast analysis, and stacking fault energy is also calculated from theextended nodes.

Structural relationship between Z and T phases in a rapidly solidifiedAl-Li-Cu-Mg-Zr alloy has been studied by high-resolution electron microscopy andconventional tramission electron microscopy. The result shows that there exist two well de-fined orientation relationships between Z and T phases. The observed structural faults in Zand T phases could be interpreted. The structrues of the two phases is closely related to eachother, certain faulted structures in one phase can be seen as the other phase when the faultedarea is extended.

The electronic structure of Ti_3Al and Ti_3Al with Nb has been studied using thediscrete variational (DV) Xα-cluster method. Analysis of the changes in the bond order (Bo)and its components, shows that the toughening effect of Nb on Ti_3Al is due to the decrease ofp-p interaction and increase of d-d interaction between atoms. The bond order has a largerincrease when Nb substitute for Ti than for Al, which makes the alloy more stable, so Nbshould take Ti site in Ti_3Al.

The properties of Fe_3Al-based intermetallic alloys at room temperature havebeen significantly improved through multi-alloying composition control and optimization ofthermomechanical process. The elongation was increased from2--3% for as-cast state to 15--20%, the yield strength up to 500 MPa. It is found that the elongated flattened grains,B_2 structure and dispersive second phase are beneficial to the comperehensive improvementof mechanical properties at room temperature.

The analytical electron microscopic in situ study on a Cu-Zn-Al alloy indi-cates that solute depleted zone occurs within baintic incubation period, and after the periodbainite nucleates in this zone by way of matensitic shear.

Studies were made of the microstructure variation during heat treatment andthe correlation between structure and room temperature tensile properties. The duplex struc-ture, composed of fine lamellar colonies and equiaxial γgrians, with superior room tempera-ture plasticity may be obtained by heat treatment at γ+α phase zone with controlled coolingrate. It is believed that its plasticity is resulted from fine grained structure and higher volumefraction of lamellar colonies.

The tensile properties and fracture characteristics of threeAl-Li-Cu-Mg-Zr(-Ag) alloys in the natural aged temper have been studied over the tem-perature range of 77--290 K. Results show that the tensile strength and ductility of the alloyssignificantly increased with the decrease of test temperature from 153 to 77 K, except theelongation of the alloy free of Ag, which kept nearly constant for the entire temperaturerange. Planar slip behavior and transgranular shear fracture are the predominant mode forthree alloys when testing at room temperature. At cryogenic temperatures, the alloys have atendency to cracking along grain boundaries, and show different tensile behavior, i.e., theoverall deformation distribution looks fairly uniform for the alloys containing Ag, in whichthe increase of cryogenic ductility may be attributed to the homogeneous deformation.

The critical void-grwoth ratio, R_c/ R_o, was measured quantitatively underSEM to the core of fracture surface of smooth and notched tensile specimens for BHW60steel at 20, -60, -100 and -140℃. Correlation between R_c/ R_0 and macroscopic fracturetoughness, V_(GC), as well as the effect of heat treated condition upon them were investigated.Results show that the R_c/ R_0 values are approximately obedient to normal probability dis-tribution at the same temperature, decrease linearly with the decrease of temperature and arerelated to V_(GC) as: V(GC)= Cln(R_c/ R_0), where C=3.5. This expression seems to be in goodagreement with the R-T model of void-grwoth and the coefficient C is insensitive to temper-ature and heat treated condition.

The rare earth La sensors were made by using polycrystallineLa_(0.95)Ca_(0.05)F_(2.95) as solid electrolyte, LaNi_5-Ni as reference electrode and Mo wire as leadwire. And the activity of dissolved La was directly determined with different La concentra-tions in molten Al at 1023 K. The results were in agreement with that of oxygen concentrationcell EMF determined by oxygen sensors. Some thermodynamic data of Al-La system at1023 K were obtained as follows: △G°_(La)=-175.2 kJ/mol, γ°_(La(s) = 5,85×l0~(-7) ε_(La)~(La)= 28.7, e_(La)~(La)=0.024

Apparent reduction rate constant, K_a, was determined by measuringCO_2 evolution with an infrared gas analyser. The relationship between K_a and Fe_tO in slagwas found to be parabolic. K_a approaches to the minimum when either the slag basicity,R<1.0 or=1.5 and Fe_tO content 50% or 70%,respectively. The activities of Fe_tO in CaO-SiO_2- Fe_tO ternary slag system at 1723 K may be calculated by using regular solution model.

Study was made of the solute content and distribution of cellular structure atdifferent growth rates in rapidly solidified Al-8wt-% Fealloy. The alloy solidified as cellularstructure with inter-cellular regions composed of many randomly oriented Al-Fe particles.At the highest growth rates, the cell-spacing exceeds the characteristic diffusion length D/vby a factor of 83. The rate of increase of the average cell composition with growth rate iscompared with that predicted by different models.

The relationships among trapping parameter, density of traps, trappingbinding energy and time-lag in electrochemical permeation experiment were studied forPd-D system. The apparent and lattice diffusivity of deuterium in palladium around theroom temperature was measured, and the deuterium trapping parameters for as cast,well-annealed and deformed palladium, as well as the binding energy between deuteriumand dislocation were obtained.

An improvement on the properties of plasma sprayed ZrO_2 ceramic coatingby laser remelting treatment has been observed by TEM, SEM, EPMA and X-ray diffractionanalysis. After laser remelting, the ZrO_2 coating changes its structure into more dense andnonporous, and more stable to thermal failure and cracking if a suitable SiO_2 doped. Thebonding of laser remelted ZrO2 ceramic coating together with adhesion layer is found to be ofmetallurgical nature. The thickness of adhesion layer and metallurgical bonding interface maybe evidently increased. With the increase of the laser output, the ceramic coating, adhesionlayer and a certain depth of substrate surface are able to be fused. A liquid Zr6Fe3o phase maybe formed between ceramic coating and adhesion layer.

(Ti_xV_(1-x))(C_yN(1-y)) particles in HSLA steel, subjected to weld thermal cycles, wasobserved to lag behind in dissolution, which reduces with the increase of peak temperature.And the coarsening rate of these particles is very slow.

The cross section microstructure of ion-plating aluminum bronze film wasstudied by TEM. The results show that the whole film consists of different morphology zones:fine equiaxied crystal, fibre crystal and columnar crystal growing in the way of twin. There areNiAl and Cu_9Al_4 phases in the film. The nucleation and growth processes of film are dis-cussed. The growth strips in vapour deposition film is found.

The mechanism of X-ray diffraction peak broadening of Fe_(50)Pd(50) alloyultrafine particles(UFP), produced by inert gas condensation method, has been investigatedby XRD, ED, TEM and EDAX. The results show that the anomalous peak broadening of thealloy UFP is caused by the nonuniformity in chemical composition. The composition broad-ening factor is decided by the diffraction angle θ and the average variation rate of the latticeparamater e_c which is caused by composition nonuniform. It can be expressed by the formulaβ_c(2θ)=4e_ctanθMean particle size is calculated by using Gaussian, Cauchy and mixed profiles. UsingCauchy or mixed profiles can lead to a better agreement with the TEM results. The results ob-tained from various profiles are close to each other when particle size is small. The discrepan-cy becomes large with the increase in particle size.

The CF/Al composite seems hard to be forming, the wettability between car-bon fibres and Al, which is mainly because of their interfacial chemical reaction, is still poorthough it was treated by K_2ZrF_6 wetting promotion. While, the wettability between SiC andAl is dependent on dissolving a small amount of SiC, coating on carbon fibre, in Al melt. Thediffusion of K, in K_2ZrF_6, through the carbon fibre surface or SiC coating may perhaps bepromoted. Molten Al may fully infiltrate the SiC coated fibre tows or fibre preforms in a veryshortterm. Thus, the fair CF/SiC/Al interfaces may be obtained by alloying the matrixwith Si, and the compattibility between C/Al interfaces and other forming problem may be