The bainitic transformation in a Cu-Zn-Al-Mn alloy has been examin-ed with TEM. The results show that the stacking faults and also the bainitic mi-drib are found at the beginning of bainite formation in the alloy. The stack-ing fault planes can pass continuously through the midrib in bainite. The growthledges occur at the broad faces and rims of bainite. The broad and narrow faces ofthe ledges are parallel to the fault plane and habit plane respectively. Both theirMiller indices are {110}_(B_2). The moving direction of ledges is parallel to the faultplane. It may be deduced that bainites in a Cu-Zn-Al-Mn alloy are initially form-ed by shear and the process of growth are governed by propagation of fault planes.

The distribution of hydrogen concentration near the notch tip of theaustenitic steel 21Cr9Ni9MnN under model Ⅰ loading has been studied by Ion Micro-probe Mass Analyser. Experimenial results show that two peaks of hydrogen accu-mulation, one at notch tip and other far apart from it, are found. The distributionof hydrostatic stress and plastic strain in front of the notch tip under planar stresscondition was calculated using ADINA non-linear finite element method. The calcu-lated result in comparison with data measured showed that the hydrogen concentra-tion peak at the notch tip is caused by trapping effect of dislocation on dissolvedhydrogen, while the other from the hydrostatic stress. The influence of stress in-tensity factor on the distribution of hydrogen concentration and the process of hy-drogen accumulation near notch tip was also discussed.

The volume fraction of the larmellar cell in HK50 alloy may beincreased with the increase of N_2 content over 0.065%. The habit plane of larme-llar carbide is {111}_γ. The distribution of N_2 changes no more before or after thelarmellar cell precipitated. The diffusion activation energy of carbon reducesremarkably with the increase of N_2 content. It is believed that the larmellar carbi-de is harmful to the high temperature creep and impact properties of the alloy.

The aging precipitation structure and its properties of the Al-Li-Cu-Zr alloys with 3 different Cu/Li ratios have been studied. Experimental resultsshow that the aging hardening of the alloys consists of two steps: the first is stre-ngthened by δ'-phase (δ'+T_1 phase in alloy No.3), and the second by δ'+T_1 phase(δ'+T_1+θ' phase in alloy No.3). The plate of T_1-phase can absorb the Li atomsfrom δ' particles when the plate bumped into δ"-phase, and therefore, these δ' pha-se particles become smaller and gradually disappear. The strength and hardness areincreased with the increase of Cu/Li ratio which cuased a decrease in plasticity.The crack mode would change from transgranular to intergranular. This is due to theprecipitation of the equilibrium phases contained Cu at grain boundaries.

On the basis of statistical data of MnS in the conventional 3%Sisteel sheets after various annealing processes, the critical inclusion factor has beenevaluated to be 20mm~(-1). The inhibition of MnS to grain growth has been moreexactly described.

On the basis of analysis of low carbon steel fracture macro-featuresand micro-processes at low temperature, definition was given of the characteristictransition temperature of brittleness, T_(pm), and its physical meaning was expounded.Discussion was carried out of physical characteristic of variation at T_(pm) in respectof the fracture toughness and property of crack arrest. In addition, research wasmade on application of T_(pm), which can given information about transition of frac-ture toughness and property of crack arrest and critical crack size, to estimation oflow temperature brittleness of low carbon steel.

High temperature shape memory effect depended on the pre-deformation temperature of the Ti_(50)Ni_(13)Pd_(37) alloy has been studied. This alloy, ofwhich the reverse transformation start temperature on heating is 620 K, has bothone-way and two-way shape memory effects. The maximum shape memory strain ofthe alloy may be obtained under pre-deformation in the range of 620 to 640 K.This seems to be related to the minimum recoverable strain energy emerged fromthe above mentioned temperature range.

TEM observation in situ on the single-side thinned specimens wasmade of the nucleation and growth of borides during boronization of steel 20 andthe influence of prior room temperature deformation. The results of X-ray diffrac-tion and electron probe microstructure analysis show that only Fe_2B formed inthe surface layer of specimens at the beginning of boronization; the atomic concen-tration of B in the surface layer increased with the increase of deformation mon-otonously; and the segregation of B atoms in the dislocation cells hindered the re-covery and recrystallization of the deformed structure of the matrix and accelara-ted the nucleation and growth of borides in the surface layer.

Studies were carried out of the precipitation in two sets of binaryAl-Li alloys by means of hardness test, DSC analysis and TEM observation. Whent healloys were aged for constant time, a peak appeared on the plot of temperaturedependence upon their hardness in the range of low temperature, and the endother-mic dissolution peak was quite distinct on the DSC curve also at low temperature.These are believed that an li-rich GP zone is formed in the alloys aged at lowtemperature, but no more GP zone if aging at elevated temperature. The hardnessof the alloys raises rapidly with coarsening of δ'-phase grains. The two endother-mic peaks of δ' dissolution on the DSC curve are related to the structural adjust-ment at twice of the δ' precipitation. The equilibrium δ-phase, being of higherthermal stability, nucleates and grows directly from the supersaturated solidsolution with the aid of the grain boundary.

The alteration of substructure of an austenitic stainless steel hasbeen investigated during constant strain fatigue. No plateau stage on the cyclicstress-strain curve was observed for the stainless steel in contrast with a mono-crystalline pure copper specimen. This may be related to its low stacking fault en-ergy. During strain fatigue under various amplitudes the substructure of dislocationin austenite alterates correspondingly. It revealed to be associated with the appear-ance change of the cyclic stress-strain curve.

The fracture mechanism of deformation-aged Al-Li alloy was approach-ed by investigating the influence of prior cold deformation on the precipitationkinetics as well as the behaviours of work hardening and fracture for Al-2.73 Lialloy. The experimemal results show that the work hardening rate and thestrength are increased and the ductility is decreased by prior cold defromation.The decrease in ductility is mainly due to the cell dislocation substructure distri-buted inhomogeneously and the hardening of precipitates free zones at grain bound-aries caused by prior cold deformation. The failure mode in the alloy is a mixedintergranular and transgranular fracture. The tendency of intergranular fracture isintensified through the deformation-aging. The mechanisms of intergranular failurein the alloy are different under various deformation-aging treatments

The time-dependent fatigue and its micromechanism of superalloyGH169 at 650℃ have been studied. Under the same stress and duration, its cycliclife in Ar is shorter than that in air. The damage mechanism is mainly of the hightemperature oxidation and fatigue interaction. The fracture surface of GH169specimen oxidized at 650℃ in air is covered with a dense and even oxide film,but in Ar, with an uncontinuous oxide particles.

Using gauge field theory of defects, the effective critical extensionforce in elastic-plastic fracture mechanics was given. The rationality of logarithmof effective critical extension force as a linear function of the fractal dimensionali-ty of the fracture was analyzed in theory. The explanation in approach to studyingmaterial toughness using the fractal has been clarified.

A method together with a new formula were developed for measur-ing the vacancy migration energy by HVEM considering the effect of surface sinkof specimen on point defects. The vacancy migration energy may be calculatedthrough the loop growth rate under electron irradiation at various temperatures.

The grain boundary cracking of the cast steel Ni9 seems to be mainly related tothe segregation of contaminantes H, S and P along boundaries. An addition of rare earth mayeliminate the segregation of these contaminantes along grain boundaries and improve the bind-ing force among boundaries, so as to reduce remarkably the grain boundary cracking.

The rate equation of reaction between PbS and PbO is da/dt=kx_(PbS)~3x_(PbO)~(-2).A transition product, PbSO_4·2PbO, is found by X-ray diffraction analysis. The reac-tion mechanism was discussed on the basis of electron transfer.

The anode reaction and current density have been investigated of theelectrowinning of Sb from jamesonite concentrate. A higher anodic current densityseems to be the major cause for consumption of much electricity, pollutation ofenvironment by alkaline mists as well as depression of deposition quality and elec-tric efficiency. A series of steps were found to be involved during the anodic pas-sivating process of Fe in NaOH solution such as adsorption, phase formation, age-ing of passivated films etc. A new anode material Fe/Ni/Co_3O_4 was developed so asto save the d. c. electric consumption over 160 kWh per t of Sb production.

The solubility of C in Mn melt at different contents of Si at 1350℃was determined. The solubility of Ca in Mn melt containing C in CaC_2 crucibleunder sealed condition at 1350℃ was ascertained. With these data, evaluation ofthe activity interaction coefficients e_C~(Si), e_C~(Ca), e_C~C as well as γ_C~O was made. The standardfree energy of solution of C in liquid Mn based on the 1 wt-% solution standard,formulated in relation to T, was also estimated. Brief discussion was made as tothe confirmability of results with those given in the literature.

A new molybdenum oxide phase existed in bomb combustion productsof Mo was found. It has been determined that this phase is a transformed MoO_3 oftriclinic system. One set of its lattice parameters was also determined from the X-ray diffraction data as α=0.4049±0.0001 nm, b=0.5079±0.0003nm, c=1.4339±0.0009nm, α=115.16±0.08°, β=90.69±0.14°,γ=105.58±0.05° and unit cell volume=0.2544nm~3.

A modified liquid phase epitaxy apparatus for semiconductor materialswas used to measure the solubility of GaAs in Bi. The solubility of GaAs in Biand two phase diagrams rich in Bi under H_2 and N_2 atmosphere were obtained. Anew phenomenon, in which the parameters Q value (quantity of GaAs dissolved inBi in fixed time but various temperatures/saturated quantity of GaAs in Bi) weredifferent from each other and there existed a maximum Q value in particular tem-perature, was observed. This phenomenon can be recognized as a common feature ofa simple binary metallic system which has the phase diagram similar to that of Bi-GaAs. The difference observed from the dependence of Q values on temperature inboth H_2 and N_2 atmosphere was discussed.

The yttraluminizing coating on the Ni-base superalloys has been devel-oped by dipping the specimen in a specially made Y-containing slurry as an under-layer and over spraying a Cr-Al slurry as a protective layer, then heating to1060℃ and holding for 1h under Ar atmosphere. Analysis by EPMA showed thatthe Y was concentrated in the intermediate zone of the coating as metallic compoundNi_5Y. After exposure to air up to 1000℃, the oxidation tests revealed that theanti-oxidation properties of the yttraluminizing coating with secondary aluminizingare much superior to that with single aluminizing only.

The pits and pit-associated fatigue crack initiation of the offshorestructure steel A537cL1 have been investigated under saltwater spray condition. Thetests were interrupted on schedule to make plastic replica of corroded specimen surfaceon which many randomly distributed pits can be found. The development of the geometricparameters of pits was obtained and the statistical distributions of these parameterswere determined. Instead of depth, the ratio of depth to width is the most domi-nant parameter in relation to crack initiation. Also, the pitting was enhanced whenlow frequency or high stress range was applied and although stress range has noeffect on the nucleation of pits, it can accelerate the initiation of cracks from pits.

The morphology, microstructure,chemical composition and electrochemicalfeature of the flame sprayed Zn-Al15 coating after corrosion test in sea water havebeen investigated. The results show that the selective dissolution of the laminar eu-tectic structure of the Zn-Al15 coating is the fundamental cause for the similarityof the electrochemical static feature to that of the Zn coating and of the kineticfeature to that of Al coating. The combined action of the laminar eutectic structure ofthe coating together with residual stress in the beginning under sea water corrosionmay induce the stress corrosion cracking of the coating, and result the interstitialcorrosion. Then, the coating will bulge and fail in localities due to embrittlementitself, stacking and expansion of corroded products under the residual stress.

The effect of the laser processing parameters on the composition unifor-mity and shape coefficient of fusion zone with laser surface alloyed Cr plated onmedium carbon low alloy steel has been studied. It was found that the compositionuniformity depends on the shape coefficient of fusion zone, and the later is a func-tion of both power density and interaction time. If the power density is certain va-lue, it is proportional directly to the interaction time. A complete uniformal moltenpool can be gotten, when the shape coefficient is between 1.6 and 3.0.

In consideration of the envelopment of γ dendrites by the Hf-richmelts, saying brazing by the melts together, at the late period of solidification of thecast Ni-base superalloys containing Hf, a heat of brazing filler alloy composed ofNi-18.6Co-4.5Cr-4.7W-25.6Hf (wt-%) was prepared. This alloy is hypereutectic. γphase is the leading phase in eutectic γ+Ni_5Hf and γ bars are surrounded by Ni_5Hfphase. At the section perpendicular or parallel to the γ growing direction, the eutec-tic morphology is cellular or laminar respectively. The content of Ni_5Hf in thealloy is 68.7 v. -%. The compositions of primary and eutectic Ni_5Hf are very similar.Ni, Co and Hf are the main elements and the solubility of Cr and W in Ni_5Hf isvery low. This alloy is an ideal brazing filler suitable to the directional or singlecrystal superalloys, and the elements are beneficial to superalloys at all. This alloyis of low melting point and of good fluidity. After brazing at 1240℃, 5 min+1190℃, 1h under 10~(-3) Pa vacuum, the microstructure of bond is as same as thatof Hf-bearing superalloy. No more Si and B will be contaminated.

The nitride in 30CrNi steel and its composition along boundaries havebeen studied by means of scanning Auger microprobe. The nitride inclusion was id-entified metallographically as Zr(C,N) containing a small amounts of Ti and O.The interfacial boundary width between the Zr(C,N) and the matrix is about 1.6μm.An Fe-rich shell is found on the fracture surface at which the Zr(C,N) appeared.The thickness of the shell is 0.1-0.8μm. The Fe concentration of its outmost layeris 3-18 at. -%, and decreases exponeatially along the depth direction.

The TiN film was synthesized by alternate deposition of Ti and nitro-gen ion bombardment under 40 keV at room temperature. The component depthprofiles and the structure of the film have been investigated by means of RBS,AES, TEM, XPS and X-ray diffraction. The results showed that the TiN films syn-thesized by ion beam enhanced deposition (IBED) are mainly composed of TiNcrystallites, sized about 30-40 nm, with random orientation. The oxygen contaminationin TiN film prepared by IBED is less than that of the deposited film without nitrogenion bombardment. It was confirmed that there is a significant intermixed layer, about40nm thick, at the interfaces. The films formed by IBED exhibit superior hardnessand improvement over the wear resistance and frictiton properties.

The phase diagrams of molten salt systems KF-LiCl-BaCl_2 and LiCl-LiF-BaCl_2 have been determined by visual polythermal method. The relationship be-tween the change of cation radius of monovalent fluoride and the areas of primarycrystal region in the phase diagrams was discussed.

An experimental study has been made of the mass transfer of Ti and Si betweenslags and molten Cu under constant oxygen potential at 1500℃. Apparent mass transfer coeffi-cients of Ti and Si in molten Cu were obtained.

An observation under TEM was carried out of the hetero-particles and stripes in-side of the vermicular graphite in cast iron specimens which were prepared by isothermally quenchingin ice-salt-water. The hetro-particles and stripes, composed of almost pure Fe and a little Si,were found on the regions of the growth direction changing of the vermicular graphite. Manytwins and dislocations were also observed to contribute to changing the growth direction and toproviding the growth steps of the graphite respectively.

The radiation of material surface by high intensity laser beams is used to producethe ultrafine powder of pure Fe and ZrO_2. The morphology, the size and the phases of the pow-der were examined by X-ray diffractometer, scanning electron microscopy as well as transmis-sion electron microscopy. In the pure Fe a considerable quantity of γ-phase was found in thepowder. In ZrO_2 powder, instead of stable phase, two metastable phases appeared.

An improvement by deducting interference method has been developed for treatingthe interference of the same order diffraction X-ray spectrum in electron probe microanalysis.The TiN compound was taken as an example of determination of nitrogen. The result showsthat the method is available.