Cyclic stress-strain responses and dislocation structures of copper sin-gle crystals with various tensile axes were systematically studied and comparedwith each other. Experimental results reveal that the evolution of microscopicdislocation configurations in a crystal and, accordingly, its macroscopic cyclicbehaviours are closely related with its orientation. Remarkable secondary slip hasbeen observed in some crystals with orientations well inside the ciystallographictriangle, which are usually considered as single-slip ones. Their cyclic behavioursand dislocation structures at saturation are similar to those of their neighbouringmulti-slip crystals. These results have constructed the experimental basis for thenewly proposed dislocation interaction model for cyclic deformation of fcc crystals,which will be described in the second part of this article.

A dislocation interaction model has been proposed for cyclic deforma-tion. According to this model, cyclic stress-strain responses and dislocation structuresof a crystal are associated with the modes and intensities of dislocation interac-tions between slip systems active in the crystal; and, hence, may be predicted bythe location of its axis in the crystallographic triangle. This model has successfullyexplained the different behaviouls of double-slip crystals and multi-slip behavioursof some crystals with orientations usually considered as singleslip ones.

Internal friction and elastic modulus of ternary Mn-Cu-Al alloys con-taining 56--60 wt-% Mn, 0--3.59wt-% Al were measured with acoustic frequency, 1kHz, in the temperature range of -150 to 150℃. It was found that when the spe-cimen was aged in the temperature range under the spinodal curve within the mis-cibility gap, the internal friction increases with an increase of the aging time andreaches a maximum value at a certain aging time which is shorter with a higheraging temperature. Two internal friction peaks which did not appear before theaging were observed above room temperature after a definite aging time. These arethe martensite transformation peak and the relaxation peak originating from thestress-induced movement of the twin boundaries. The former peak shifts towardhigher temperatures with an increase of the aging time, whereas the relaxationpeak appearing at 15℃, is independent of the aging time and temperature. The ac-tivation energy associated with the relaxation peak was found to be 0.56 eV whichis about the same as that of the relaxation peak in binary alloy containing 90wt-% Mn. It was also found that the hardness, strength and the brittleness of thespecimen increase when aged below the spinodal curve within the miscibility gap.The addition of Al enhances the strength but reduces the internal friction of thespecimen. A choice of suitable aging time and temperature can give an optimum com-promise of high strength and high internal friction. Analysis of experimental re-sults suggests that spinodal decomposition leads to Mn-rich zones in the specimenand thus causes the phase transformation and the change of mechanical propertiesof the specimen.

Some characteristics of plate martensite in a 1.03%C ferroalloy hasbeen studied by using the transmission electron microscopy. The habit plane of theplate martensite in this ferroalloy was found to be close to {224}_f. The morpholo-gy, distribution, coalescence and curving of martensite as well as the substructurein both martensite and austenite have been observed. The mechanism of both nucle-ation and growth of the martensite have been discussed.

The kinetics of the isothermal precipitation of (Nb, V) CN in Nb-Valloys has been investigated by using the Formastor-press simalator and the extrac-tion replica method. Under four deformation amount (0%, 10%, 30%, 50%) and threetemperatures (1100℃, 1000℃, 850℃), four types of kinetic curve were found.

The present work is to study the effect of phosphorus on the anneal-ing texture of a low carbon steel at different cold rolling and annealing conditionby means of pole-figure, inverse-pole figure and orientation distribution function(ODF) method. The microstructure and distribution of phosphorus in steel sheetare studied by means of metallography, scanning electron microscope (SEM) andelectron probe microanalysis (EPMA). The results show that phosphorus promotethe formation of the fiber texture of <001> parallel to the rolling direction and<111> normal to the sheet surface. The texture was found to be affected mainly bypreannealing temperatures, promoted at 390℃ or 590℃, and retarded at 490℃. Atthe preannealing temperature promoting the formation of texture, phosphorus segre-gation to the interior of grains is observed. It seems that the formation of the fi-ber texture may be associated with the segregation of phosphorus.

The end grain attack of LD10CS aluminium alloy plates during che-mical milling in hot aqueous solution of sodium hydroxide has been studied. Theresults show that the microsegregation of some components, i.e. Cu, Si etc., is themain reason of the end grain attack, and it is affected by the conditions of heattreatment as well. The end grain attack significantly minimizes while some technicalmeasures which are beneficial to the reduce of segregation were taken during meltingand casting.

The aging response, tensile and impact properties of two kinds of Al-Li based alloys have been studied. The microstructure, deformation as well as frac-ture behaviour have been observed by SEM and TEM. It has been found that themechanism of deformation and fracture for different heat-treated alloys with thesame chemical composition is quite different. The cause led to the drop of ductili-ty, toughness as well as anisotropy in peak-aged alloys have been analysed. Finally,possible methods to improve the ductility and toughness of the alloys have beendiscussed.

Study of the solidification process of both Al-Si and Al-Cu alloysproved the presence of acoustic emission phenomena. Two peaks of count rate hasbeen observed. The total counts of both peaks increases with the increasing hydro-gen content of the alloy. The mechanism of producing the acoustic emission hasbeen discussed. At the same time, results obtained by other techniques strongly sup-port the good correlation between the acoustic emission and hydrogen releasing dur-ing solidification. The bubble nucleation between dendrite arms is the main causeof the first peak, while the fracture of the bridge connecting the interdendrites atthe later stage of solidification is the main cause of the second peak. It is proba-bly due to high pressure the hydrogen evolution and accumulation created by in theinterdendritic region.

The cleavage fracture mechanism of acicular bainitic weld metal insteel 15MVN has been investigated, SEM observation of a special specimen for re-vealing simultaneously fracture surface and microstructure shows that the cleavageof the weld metal is initiated by M-A constituent. The 95th percentile equivalentdiameter of M-A constituent controlls the cleavage fracture stress of the weld me-tal.

The growth rate of creep cracks and the times to initiation of crackand to rupture of specimen (t_(rc) and t_r) were measured by means of electrical poten-tial method using single edge-notched specimens at 700℃. The field near the cracktip under steady-state creep was represented by energy rate integral (C), and thegrowth rate as a function of C has been obtained. The agreement between the pre-dicted and observed t_(rc) values is quite good. It was found that the addition ofsmall amounts of Mg and Zr causes t_(rc) and t_r of the specimens to increase signifi-cantly.

According to the misfitting dislocation theory, a method of theoretical calculationwas developed for the spedific energy of the semicoherent interface between microalloy carboni-trides and austenite matrix. The calculating formulae were derived and the results were satifac-torily applied on the research works.

The microstructure of Cr_(25)Ni_(20) stainless steel under plastic deformation up to 50%has revealed an even distributed twins, microtwins and shear band. The σ-phase formation in800℃ aged specimens is accelerated by its nucleation on either deformed twins or recrystallizedgrain boundaries under less or more deformation respectively. In the recrystallization zone, the rec-rystallization is prior to the precipitation of σ-phase. Although the recrystallization may acceler-ate the formation of σ-phase, yet it is not essential. The twins and microtwins, produced by de-formation, may also provide the additional nucleation sites.

The macrosegregation formation in an ingot and the influence of rotat-ing mould upon it were analysed on the basis of the interdendritic flow. When theingot mould rotates unidirectionally, the centrifugal volume force acts on all innerparts and when the ingot mould rotates attenately, the tangential alternate force isalso formed, and both have various influences on the different modes of interden-dritic flow. It is shown that as the ingot mould rotates unidirectionally or alterna-tely with moderate angular speed, the interdendritic unstable flow may be control-led effectively and the formation of segregation may be restrained. Thus, it seemsto be significant for reducing the segregation such as A-type, etc., in the steel in-got.

Electrolytic extraction-radiometry and microradioautography tech-niques were used to study the distribution of nodulizing element Ce and anti-nodulizing element S in phases of high purity Fe-C-Si alloy. The results show that,besides forming inclusions, most of Ce atoms concentrate in graphite firstly. As theCe content increase, the concentration of Ce in graphite tends to saturate, relati-vely large amount of Ce dissolves in the alloy. Usually, the sulphur also concen-trates in graphite, however, it may exist in the form of FeS at the eutectic colonyboundaries, if the concentration of S is at a quite high level. Very little amountof S dissolves in the alloy. The morphology of graphite depends upon the degreeof saturation of Ce. It appears as nodula when Ce was saturated, and as vermicularwhile it was semi-saturated.

The gradient of the equilibrium melting temperature on liquid side ofadvancing solid-liquid interface has been derived. From it, a parameter, H, used forevaluating the ability of grain refinement of solute elements has been proposed.Experiments on Al-base alloys show that the grain size of alloys decrease withincreasing H value. This indicates that parameter H can be used as an index forselecting the grain refiners.

Liquid iron containing Nb, Mn and Si elements has been equili-brated with MgO-SiO_2-MnO slag melts at 1600℃ in a Mo wire-wound resistance fur-nace with a duration of 4 hours. The oxygen activities in liquid iron were mea-sured with oxygen sensors. Using the known equilibrium constants of concerningreactions and the oxygen activities in liquid iron, the components activities in theslag melts can be calculated. It was found that the partition ratios of Nb, Mn andSi have a close linear relationship with α_(FeO) in logarithmic scale. The dependenceof Nb partition ratio on mole fractions of the slag components was also obtained.

The isothermal section of the W-Ni-Cu ternary system at 1017℃ wasdetermined by means of diffusion couple sepecimens, EMPA and X-ray diffrac-tion. Body-centered tetragonal Ni_4W and orthorhombic NiW but NiW_2 observedin the W-Ni binary system at this temperature. The solubility ranges of W andCu in Ni_4W are 16.95--20.51 at-% and 0--4.36 at-%, respectively. The maximumsolubility of W in γ(Ni) is 13.11 at-%

Electric resistivity measurements and X-ray diffraction analysis wereperformed to study the isothermal phase transformation in amorphous Au-Siribbons with eutectic composition prepared using melt-spinning technique. A seriesof phase transformations take place spontaneusly at room temperature and accelerateat elevated temperatures. Four stages of the transformation from amorphous state tothe equilibrium state can be distingushed. Discussion on the structural character ofthe metastable phases indicates that Hume-Rothery electron compounds and size fac-tor compounds could form during isothermal aging.

Boundary conditions constructed by two typical geometrical config-urations related to the manufacturing methods of bronze process and tin-rich Nbtube method have been considered in a diffusion model in which the diffusion ofSn in CuSn matrix plays a major role is assumed. The dependence of thickness ofNb_3Sn layer on reaction time has been derived. It is shown that the growth rate ofNb_3Sn relates to the configuration of the superconductor, the geometrical parametersof Nb filaments and CuSn matrix. The theory are qualitatively consistent with theexperimental results.

The magnetic properties of Nd_2(Fe_(1-x)M_x)_(14)B (M=C, Si) compoundshave been investigated. Substituting Fe by a small amount of metalloid C and Siatoms, the compounds are in tetragonal structure and have uniaxial anisotropy. Thesubstitution of C for part of Fe makes the Curie temperature and the intrinsic coer-civity of bond samples decrease at low temperature. The replacement of Fe by Simakes the Curie temperature increase with a maximum at the vicinity of x=0. 15.When the range of the content of Si is 0≤x≤0.10, the coercivity distinctly in-creases at room temperature, from 62.7 kA/m at x=0 to 138.7kA/m at x=0.06, wherethe residual magnetization has a maximum; at the mean time the saturation magne-tization decreases only by a small amount.

In a thermally demagnetized state, the matrix grains in (NdPr)_(16)Fe_(76)B_8 permanent magnet, in general, are the multidomain structure, i. e., 180°plate-like individual domain and a few spike-like or mazelike domains. The averagewidth of domains is measured as 1.5μm. The grain size of single-domain is observedto be some about 1μm and particularly up to 3μm. The calculated domainwall energy, γ=3.6 MJ/m~2, the exchange constant, A=4.5×10~(-11)J/m, the domainwall width, δ=15.7nm, and the critical grain diameter of single-domain, D_c=0.5μm. The dependence of high magnetic field gradient near grain boundaries on differentmagnetization direction in the adjacent magnetic domains on the both sides of grainboundaries as well as the effect of microstructure on the values of K, A and δwere also discussed.

Surface oxidation of polycrystalline nickel foil in air and purewater at different temperatures and the thermal stability of the surface oxides havebeen investigated by means of XPS. In addition to NiO, Ni_2O_3 is formed especiallyafter long periods of air exposure. Nickel surfaces are much less reactive to purewater than to air. The thermal stability of the surface oxides is related to oxidativetemperature. The surface species of oxides formed by air exposure at temperaturesbelow 120℃ can be reduced into nickel metal after heating the sample in vacuumat 300℃ for only 10 minutes (in the case of room temperature) to 1 hour (in thecase of 120℃). This reduction is caused by reaction with surface carbon contami-nants. However, the surface species of nickel oxides formed by air exposure withheating at temperatures above 200℃ can not be reduced into metal after heatingthe sample in vacuum at 300℃ for 1 hour.

The martensite microstructure, amount of retained austenite and itscarbon content in 40CrNiMo steel quenched at various conditions have been in-vestigated by using transmission Mossbauer spectroscopy at room temperature. It wasshown that the toughening effect of high-temperature quenching and the thermome-chanical quenching has little correlation with the amount of retained austenite.

The resistance against localized corrosion of 1Cr18Ni9Ti microcrystals with nor-mal grain size and bcc structure obtained by magnetron sputtering has been compared. Two kindsof microcrystals with (110) and (211) textures respectively were obtained under different sputter-ing conditions. Both microcrystals were found to have better resistance against localized corrosionthan the crystal with normal grain. The microcrystal with (110) perferred orientation has largerresistance to localized carrosion than that with (211)preferred orientation

The temperature dependence upon viscosity and the viscous flow of the amorph-ous state of Ni-P binary alloy have been investigated on the basis of its surface tension anddensity measured. An expansion for the temperature dependence upon viscosity of the Ni-P alloyfrom liquid to amorphous solid is derived as: η=C·exp[(B+bT~(1-1/T))/(T-T_(vs)~0)]

The diagram of Ag-Cu-Bi system was constructed from the investigation of 12internal sections by DTA heating as well as cooling curves in an atmosphere of dry N_2. The com-position of ternary eutectic point melting at 258℃ lies in Ag(5.0)-Cu(0.5)-Bi(94.5) at.-%.The liquiduses of Ag-Cu, Ag-Bi and Cu-Bi binaries were reinvestigated.