A TEM study was made of the bainitic transformation in a Cu-Zn-Al alloy.The results show that initial α_1 plates are free of stacking faults. One side of the bainite plateduring their early growth stage is even while there exist three-dimensional superledges on theopposite side. The broad faces of the superledges are parallel to the habit plane, the spacingand height are ca 50--230 and 10--40 nm respectively. The ledges are mobile. Bainite thickensby means of the moving of the ledges.

The growth morphologies of MC type carbide in a directional solidificationwas described quantitatively by means of the fractal analysis. The relationship between the in-formation dimensionality of MC evolved from the lenient branch-leaves into developedbranch-cluster with the increase of the solidiflcation rate, and the information dimensionalityof MC presented the exponential law with the change of solidification rate. In combinationwith the thermodynamic of nonequilibrium, the physical mechanism of MC morphology evo-lution was discussed when the controlled parameter-solidification rate changed.

The relation between the Stress intensity factor K_I~* required for brittle crackinitiation and propagation and the fractal dimension D_F of the fracture surface was derived,l.e.lnK_I~* =(1/2)ln2γE'+(1/2)ln(d_f/L_0)·(1-D_F)where d_f is the fracture unit, L_0 a material constant, γ the real surface energy andE=E/(1-v~2). The surface energy can be calculated from the measured linear relation of thelnK_I vs D_F The equation is not only suitable for the overloaded cracking but also for the de-layed cracking (e.g. hydrogen induced cracking and stress corrosion cracking). The experi-mental results showed that the hydrogen induced delayed cracking occurred inTi-24Al-11Nb during charging, and the threshold stress intensity value was low i.e.K_(IH)/K_(IC)= 0.43. The relation between the stress intensity factor K_I~* and D_F measured by ex-periment was consistent with the theoretical equation.

The preparation of FePd alloy ultrafine particles (UFP) by inert gas condensa-tion technique was studied. The properties of the products were measured. The results showthat the composition of the master alloy and the activity coefficient of the components havestrong effect on the products. The single phase uniform alloy UFP can only be obtained byevaporating the alloy with the composition of N_Fe = 0.5. The stability of Fe_(50) pd (50) alloy UFPis higher than that of Fe UFP. The coercivity of Fe_(50)pd_(50), is several times higher than that ofcoarse grain powder with the same composition and can reach the value more than 4.30×10_4 A/m.

The residual strength and relation to the cavitation of as-warm rolledAl-Li-Cu-Mg-Zr alloy have been investigated after superplastic deformation under differ-ent tensile conditions. Under certain extent of strain, the specimen deformed at a high strainrate has less cavity and higher residual strength than that at low strain rate. Whiledeformation to a large strain, the specimen deformed under test at strain rates of two-stage,i.e., at a quick one first and slow down afterward, has less cavity and higher residual strengthin comparison with that of a single stage. The relationship among residual strength, cavitationand superplastic tensile conditions has been discussed by considering the deformation-in-duced continuous recrystallization occurred during the initial stage of superplasticdeformation.

Deep undercooling for Ni-base alloy, i.e., (Ni_(0.53)Fe_(0.33)Co_(0.14))_(73)B_(17)Si_8Nb_2, wasobtained by technique of auto-separating denucleation of molten glass. The solidification ofthe undercooled Ni-base alloy is observed to be in a mode of twin growth. Mechanism on theformation and growth of twins was approached by studies of composition, structure andmorphology of the alloy, together with the solidificatiion of deep undercooling alloy melt. Theundercooling, crystal lattice and composition of the alloy seem to be the most important fac-tors in the formation and growth of twins.

The effect of solidification rate on the solid/liquid interface morphology,microstructure and longitudinal tensile properties of unidirectionally solidified Fe-C eutecticalloy was investigated. With the help of computer image analysis system, the irregular degreeof graphite flakes was defined, which can be used to represent the graphite flake distributionstate. Plots of variation of the solidification rates vs irregular degree and tensile properties arepresented.

By comparing the solute distribution between spherical growth and directionalsolidification, it is found that the steady-state of solute distribution in directionalsolidification can not exist in spherical growth.

A process extracting Cu, Ag, Pb and Zn from a bulk sulphide concentrate withFeCl_3 solutions was investigated. The kinetics of the process and effective parameters wereexamined based on a model of non-reaction shrinking core and an approach of non-linearregression. It was found that the rate of Cu dissolution in the process was controlled by a sur-face reaction which was a half order with respect to Fe~(3+) ions and zero order with respect toCl_-ions. More than 96% Cu, 95% Ag, 90% Pb and 9l% Zn were extracted while over70% sulphide were converted to elemental S and more than 97% of Au were left in theleached residue under the conditions studied. Thus, the leaching process by FeCl_3 and NaClsolution was a more potential technology for pre-treating of Au-bearing sulphide concen-trate and recovery of valuable metals.

Hydrophobicity-hydrophilicity balance relationships for collectorlessflotation, including self-induced and Na_2S-induced flotation, have been established, throughsolvent extraction-chemical analyses of neutral sulphur (S~0) from sulphide mineral surfaces,measurements of pulp potential and flotation tests. They may be indicated as [S~0]/[OH~-]and[S~0]/([OH~-]+[HS~-]) respectively. The neutral sulphur extracted was considered to be re-sponsible for the hydrophobicity, and the amount of which was controlled by pulp potential.The critical value of neutral sulphur amount was proposed as a new concept, and was used toindicate the hydrophobic degree and flotation behaviour. The hydrophilicity was attributed toOH~- ion for self-induced flotation and both OH~- and HS~- ions for Na_2S-inducedflotation. At a given pH value, hydrophobicity and floatability increase with the amount ofneutral sulphur extracted. At different pH values, the higher pH results in the strongerhydrophilicity, and hence hydrophobicity and flotation require more amount of S~0. The lowerpH values are in correspondence with smaller amount of S~0. The critical value of amount ofS~0 to Na_2S-induced flotation is higher than that to self induced flotation because of thehydrophilicity of HS~- ions.

The dissociation model of complex ion, combined with the sublattice solutionmodel is applied to calculate constants and heats of dissociation successively of complex ionAlF_6~(3-). The results show that AlF_6~(3-)in LiF-AlF_3 melt has a stronger tendency todissociation and smaller heats of dissociation than that in other alkali fluoride and the alumi-num fluoride system. The molar concentration of each composition in LiF-AlF_3 melts arecalculated, and the thermodynamic properties of mixing for LiF(l) and AlF_3(s) are calculatedas well. The results of calculation agree with experimental results.

The internal oxidation of active solute Eu in Pd-Eu alloys has been studied inair at 800--1200℃. It was a nucleation and growing process of stable oxide Eu_2O_3 controlledby diffusion mechanism: oxygen entered to internal layer and Eu diffused towards outer layerand surface through bulk and grain boundary diffusion, this caused non-homogeneous dis-tribution of oxygen and Eu. For wire samples with dia. 2mm, the dependence of the internaloxidation depth (ξ) on the reaction time (t) could be expressed as ξ= Kt~n, here n=0.5 at 800--900℃, and n=0.75 at 1200℃. The activation energy of Pd-0.56at.-%Eu alloy was deter-mined to be 150 kJ/mol.

Crystallization phases, morphologies, and electronic structures, as well as thedistribution of metalloid atoms in the nanocryatalline Fe-Cu-Si-B alloys were studied bymeans of XRD, TEM and TMES. The lattice constants of α-Fe(Si) in the alloys may reduceobviously with the growth of grains. The B atoms in the alloys exist in two states and they re-main unchanged in feature as grain growth; while Si atoms occur short range order and itchanges over the grain growing.

The surface states and activities for hydrogenation catalysis of both amor-phous, made of mechanical alloying, and crystalline Ni_(50)Pd(40)Si_(10) alloy have been investigatedafter HF solution treatment. It is believed that the activity of the amorphous alloy is superiorto that of crystalline one by about 4 times.

Microstructure of the cast SiC_p/2024 Al composites, containing 5, 10, 15 and20 v.-% SiC particles, under peak-aged state and the strengthening mechanism have beenstudied by TEM observation and Vickers hardness measurements. An increase of dislocationdensity in the matrix and slight reduction of subgrain size may be caused by thereinforcement, but the hardness of the matrix increases no more. Tensile tests show that theelastic modulus and work hardening index increase obviously, and the initial flow stress de-creases first and increases afterwards with the increase of volume fraction of SiC particles. It isbelieved that the stress concentration and the deformation constraint by the reinforcementare two main factors in control of the plastic deformation and strengthening of theSiC_p/2024 composite.

Investigation was carried out of titanizing the plain steel by technique ofglow-discharge plasma with arc source. Microstructure, Ti distribution and phases occurredin the infiltration layer and their related processing parameters were examined and discussed.

Laser surface melting of AISI 304 stainless steel has frequently beneficial effecton surface modification due to the high quench rate by self conduction of heat as quenching,and has a disadvantage that a considerable amount of tensile stress was introduced.It could berelaxed by neon implantation. Principle and method for measuring the stress relax in 0.1 μmthick surface layer were explained in detail for showing the Ne effect on it.