The dispersoid phase Al_(20)Cu_2Mn_3 in a 2024 Al alloy is commonly composed of twins. An observation of corresponding high resolution image shows that the twin boundary plane is a glide plane other than mirror one. Two neighbouring components of twins are not symmetry of reflection or rotation, but of glide reflection. The "diamond" glide plane is (101) and the glide vector is (1/4)(a--c). Components of twins in the phase take shape of prism with the longitudinal edge being parallel to [010] and side faces being {101} and {100}.

The relationship between structure and hysteresis of phase transformation tem-perature in NiTi shape memory alloy has been investigated by means of TEM observation, positron annihilation and electrical resistivity measurement. The sequence of hysteresis for the alloy aged under different regimes was found to be: plate martensite > R phase > tie--like martensite. The reversible displacement of phase boundaries of these transformations is blocked by the coherent stress field around Ti_(11)Ni_(14) phase particles. A linear relationship between Sparameter of positron annihilation and maximum values of temperature hysteresis showed that the mismatch dislocation and elastic stress field established by Ti_(11)Ni_(14) phase precipitation arethe main factor to determine the temperature hysteresis of phase transformation in NiTi shape memory alloy.

The elastic limit of single--phase alloy Nb--2Mo--2Zr--1Ti is higher as recovered state in comparison with as cold--rolled or recrystallized one. For Nb--40Ti--5.5Al alloy of age--hardening type, the elastic limit is lower as cold--rolled state, but increases considerably after proper aging. However, its elastic modulus changes no more, so the stored--energy (σ_e~2/E) may raise significantly. The temperature dependence on elastic modulus for pure Nb as intensely cold--worked or recrystallized state is anomalous. This anomaly may disappear after reco vered treatment of intensely cold--worked state at 600℃ for 4h, and may change no more after that of recrystallized state. The anomalous behaviour of elasticity was also discussed on the non--magnetic Nb.

A proper addition of Mn to Fe--C alloys could delay the isothermal transforma-tion and change the shape of the TTT curves of the alloys. The concentration of Mn at α/γ in-terfaces and their neighboring matrix were measured by STEM / EDAX. The results show that the partition of Mn between α and γ occurs at higher temperature but not at lower temperature. There exists certain temperature range with the strongest Mn concentration spike at the inter-face even though Mn partition between α and γ is not found at the temperature on range. The fact that temperature at which the highest Mn concentration spike occurs is correspondent with the bay temperature on TTT curves shows that the change of TTT curve shape is due to the solute drag effect and solute drag--like effect which are caused by the enrichment of Mn at the α/γ interface.

Effect of microstructure on the mechanical properties of a precipitation strengthening Fe--Ni--Co based low expansion alloy, Incoloy 907, has been investigated under different heat treatments. the dispersed γ phase is found to be the principal strengthening phase in the alloy. The microstructure of the alloy with even dispersed fine γ' phase seems to have the best match of its mechanical properties. However, it will be worsened if the alloy aged at some higher temperature or overaged to precipitate needle--like ε phase.

Studies were made of the calculation of fractal dimension of transverse impact fracture surface, and of the correlation between impact toughness of steel and parameters of free-cutting phase by means of the developed fractal geometry model of crack propagation. It is believed that the area fraction f, of free--cutting phase is negligibly influential to the longitudinal impact toughness, as f《 1. While the configuration, saying ratio of length to width,of free--cutting phase is inversely ?nfluential to the transverse impact toughness. This may be the reason why the transverse impaot toughness of free--cutting steel containing more rare earth contrast to sulphur is even higher than the low sulphur base steel.

The microstructure and properties of the rapidlysolidified Al--Li--Mg--Zr alloy,in relation to the particle size of supersonic atomizing powder, have been investigated. The finer the size and the structure of powder are, the higher the strength of the alloy will be. While the overfine powder may worsen plasticity of the alloy. The proper powder seems to be sized 40--100 μm.

The precipitation of x--phase, σ--phase and carbides may be restrained or elimi-nated by laser melting the plasma sprayed Cr--Mo alloy coating, in which austenite of abundant block usually occurred, on medium carbon low alloying steel. The corrosion resistance of this coating to 0.5 mol / L H_2SO_4 was examined to be superior to that of 18--8 stainless steel. The laser alloying Cr--Mo coating also has excellent resistance to pitting corrosion, and no pitting appeared even it immersed in a medium containing Cl~(-) ions.

The intensity distribution curves for austenite stainless steel 1Cr18Ni9 after 1080℃ W. Q. and de-formed under uniaxial tension at different degrees of strain have been examined by step scanning X--ray diffraction technique. The effective domain size, dislocation density inside domains, dislocation istrubutionparameter, density of stored energy, etc. were obtained by profile analysis. In comparison with TEM observation,the grain is similar in size to subgrain, but the minimum width of stacking faults differs with the characteristic one, which may be related to the variation of stacking fault width

The intergranular carbides may significantly increase rupture life and ductility of the Fe--15Cr--25Ni alloy. This seems due to the grain boundary sliding and diffusion hindered by precipitation of intergranular carbides, so the nucleation and growth rate of crack or cavity are reduced.

A comparative study was made of the reduction kinetics for high temperature smelting of vanadium--titanium--containing magnetite, together with Hainan iron ore, using iron bath method. Three peaks were revealed on the reduction rate curves for the magnetite,while one peak only for Hainan ore. Under the same conditions, the smelting reduction rate of the magnetite was found to be lower than that of Hainan ore. The rate increases evidently with the increase of the bath volume. The expressions of smelting reduction rate were suggested forthe reduction with and without iron bath respectively.

Under inert atmospheres and 1473K, the evaporation rate of SnS fromSnO--FeO0-SiO_2 and SnO--FeO--CaO--SiO_2 slags mixed with FeS was investigated by meas-uring the weight loss and composition of samples. The experimental results show that during sulfide fuming process the evaporation of SnO from Slags is negligible in comparison with that of SnS. Addition of CaO to slags can enhance the evaporation rate of SnS. The differential rate equation of evaporation may be expressed as:-d(%Sn) / dt = k(%Sn)(%S)where, the apparent rate constant k was found to be 4.20×10~(-3) for SnO--FeO--CaO--SiO_2 sys-tem and 2.88×10~(-3) for SnO--FeO--SiO_2 system, respectively.

The contact angle of liquid Ag with solid W and its temperature dependance were examined by sessile drop method under various atmospheres, e.g.vacuum, Ar, H_2 and cracked NH_3. The O_2 partial pressure in the atmosphere is found to be the major factor. An obvious improvement on the wettability may be made by a trace amount of Ni, Cu or Ce added to liquid Ag. The contact angle near M.P. is then narrowed from 69 to about 10--20 deg.

A new microstructure model is developed for amorphous alloys, so called Clus-ter model, in which the amorphous phase is thought of composing of randomly distributed or-dered clusters of different sizes. Thermodynamic calculation on this model deduces a parameter describing the glass forming ability of metallic alloys: a_c=(1-2.08/φm)T_g/ T_m, where T_g is glass transition temperature, T_m is the melting temperature, and φm is entralpy change of melt-ing. It is believed that easy glass forming alloy systems have larger values of a_c This new criter-ion of GFA not only provides the theoretical background for several GFA criteria in the litera-ture cited, but also can predict the GFA of many alloy systems more reasonably and accurately.

Ion beam Sputtering Profiling in combination with SIMS technique was em-ployed to investigate the Al diffusion in Fe_(78)Si_9B_(13) amorphous alloy. Between 320℃ and 380℃,the diffusion coefficients vary from 2.43×10~(-22) to 2.01×10~(-21) m~2s~(-1), and an Arrhenius rela-tionship was established as: D_o = 2.02×10~(-12) exp (--1.17 / kT)

An evident improvement on activation properties of hydrogen storage was made by sputtering an amorphous coating of commercial Si on TiFe alloy. SEM observation revealed an obvious difference betwwen the morphologies before and after hydrogen storage for TiFe al-loy with or without amorphous Si coating. It is believed that this may be quite a developable hydrogen storage material.

Using liquid quenching technique, the change of growth mode of graphite in cast iron melt was analysed. Based on the interface structure theory of crystal growth, the concept of multiplication of spiral growth steps was advanced and two basic multiplication models were given out. It was proposed that multiplication of spiral steps is responsible for the changeof growth mode of graphite in cast iron melt. The modifying elements such as cerium promote multiplication of spiral steps, which is regarded as the core of modification. Origination of screwdislocation and branch of the sector blocks in radius direction, both of which are essential to spheroidization of graphite in the melt, are caused by multiplication of spiral steps; and so is thickening of graphite plates.

According to probabilty theory and atomic activation on bonding interface of metals, a mathematical model was developed for the atomic interfacial reaction during diffustion bonding. The effect of parameters of bonding processing and material on the bonding strength was then gained. It was suggested that the activation centre of atomic interfacial reac-tion of bonding may be, in situ, the boundary dislocaion and its elastic stress field. A substantial agreement about the quantitative prediction of the model was made with the results of diffusionbonding experiments for 7075 Al alloy