The meta-bainite which is composed of bainitic ferrite(BF) and retained austenite(A_R) was obtained in silicon-containing steels held in the temperature range of bainite formation for a short time. It was confirmed that BF is supersatuated with carbon by the facts that Spinodal decomposition occurs in BF and that the quantitative data of carbon content in BF was obtained by a new equation based on the X-ray diffraction data. The dislocation loops at BF/A_R boundary, which is very similar to that of lath martensite, and stacking faults in A_R and twins in BF were found by TEM. Based on the results, a three-dimensional model of hainite shear formation controlled by diffusion of carbon was suggested.

A dislocation model of ferrous martensite nucleation and growth was proposed by means of the K-S orientation relationship of martensitic transformation, and the mathematical formulas of martensitic shear process were derived. These formulas might remedy some defects of phenomenological theory of martensitic transformation. A new crystalline geometry explanation was advanced for martensitic substructures(twins and dislocations) in steels.

The original structure of Fe-30Ni alloy consisted of deformation-induced martensite, quenching martensite and retained austenite. After heating to different temperatures the ODF of austenite and martensite were determined. The result shows that at lower temperatures the texture of austenite reverts to the original texture of cold rolled austenite and the transformation is carried out by a shear-mechanism with strong variant selection. In the higher temperature range the transformation is carried out by an oriented-growth mechanism and the texture of retransformed austenite deviates from that of cold-rolled austenite. From the difference of ODF a " transformation-stop" temperature has been found, which is orientation-dependent and corresponding to the change of transformation mechanism. For the orientation with higher transformation-stop temperature, the transformation controlled by an oriented-growth mechanism will begin later.

The possibility of manufacture of titanium nitride by microwave carbothermal reduction of titanium oxide was discussed. The mechanism and thermal dynamics of the reaction process was also studied. The resuls showed that the technology has unique advantages compared with the conventional carbothermal reduction method, for example it can not only lower the reaction temperature, shorten the synthesis cycle, but also can refine the powder particles, so the reactivity of the powder is improved.

The embrittlement kinetics of alloy Fe-15Cr-4Al during aging at 500℃ was determined and the changes in microstructure and fracture behavior after aging were investigated by internal friction, TEM, EPMA and SEM. It was found that the aging embrittlement consisted of two stages. In the first stages (0-100 h), the rapid precipitation of carbide around grain boundaries of α-phase played an important role. In the second stage (100-1000 h), the action of Cr rich α'-phase precipitated uinformly in α-phase became more important. For alloys Fe-15Cr-4Al-Y with 0.2 and 0.4% Y, the EPMA results indicated that the carbon atoms were captured by Y_2Fe_(17) phase in these alloys, and no any carbide precipitation could be detected in the aged alloys by TEM, which is the reason why the Fe-Cr-Al-Y alloys have high plasticity during aging at 500℃ for 1000 h.

Solution and escape of hydrogen in low-carbon steel have been studied by means of electrolysis-cathode-hydrogenating under plastic deformation and under tensile stress. Some empirical formulas of diffusivity were obtained by the regressive method. The results revealed that the diffusivity during solution is greater than that during escape and the larger the plastic deformation or tensile stress, the larger the solution diffusivity and the escape activation energy.

The diffusivity, permeability and solubility of hydrogen in DD8 and Rene'N4 superalloys were measured in the temperature range of 30t-420℃ by using ultrahigh vacuum gas permeation technique. The effect of defects on diffusivity and the reason of exothermic reaction of H-solubilization were analyzed. The results show that, in the testing temperature range, the diffusivity, permeability and solubility of hydrogen in DD8 and Rene'N4 superalloys are all in agreement with Arrhenius relationship, and the presence of voids is not the reason of exothermic reaction of H-solubilization.

A new geometric model for predicting ternary thermodynamic properties from binaries is suggested. The model quantifies the asymmetric degree of the system with an exponent weight function according to the thermodynamic criterion, so as to avoid human interferences of choosing asymmetric component. It compares the similarity between every pair of binaries point by point, so that it can be applied to the system where the binary models do not cover the whole domains of compositions.

The influences of implanted yttrium with doses of 1×10~(17), 1×10~(16)Y~+/cm~2 on the growth stress of oxide scales formed on aluminized Ni-15Cr-6Al alloy were studied by using apparatus of oxide scale stress measurement. The experimental results indicated that Y~+-implantation at the two doses had no effects on the oxidation kinetics of the alloy, but decreased the growth stress in the oxide scale formed at 1100℃. The results are discussed. The reason that ion implantation with two doses decreases the growth stress and improves the adhension of alumina scale may be that Y~+- implantation changes the oxidation mechanism of the scale and facilitates the plastic deformation of the scale.

The room temperature ductility of Fe_3Al alloy with environmental embrittlement at room temperature can be improved nearly by three times by electro-brush plating copper or nickel on the specimen surface. SEM observation showed that a transition layer between the surface coating and the matrix formed during plating and the fracture surface of tensile specimen exhibits partially dimple morphology.

A mesoscopic discription on the yield stress of nanocrystals was proposed by regarding the nanocrystals as a composite of crystalline matrix and inclusion of intercrystalline layers. By introducing effective yield stress and effective modulus, a range of critical size, over which the deviation of yield stress from Hall-Petch prediction will occur, was estimated for several typical nanocrystals, and the range depended sensitively on the properties of intercrystalline interfaces. Comparison between the obtained results and the experimental data could explain the size effect on yield stress quite well in the given range of nanocystalline size. The dependence of yield stress on grain size could be divided into four regions-linear, nonlinear, abnormal deviation and indefinite region. A method was suggested to determine the elastic modulus of inclusions starting from the mesoscopic analysis.

Adhesion strength of diamond film with substrate WC-6% Co (YG6) subjected to different pre-treatments was studied. It was found that the adhesion was greatly increased by excimer laser irradiation pre-treatment. The mechanisms responsible for this adhesion enhancement are due to the selective evaporation of cobalt and, to a larger extent, due to the "anchoring effect" resulted from the surface modification (roughening) by the energetic excimer laser beam.

The rhyologic behaviors of the alloy ZA27 in the range of 385-390℃ and 400 -430℃ can be described by six element and five element model respectively. Based on these models, the stress-strain equations were deduced, and the creep, reverse creep, loading, and unloading characteristics were discussed. Rhyologic parameters of the alloy at different temperatures were calculated from the experimental results. According to the phase diagram and DTA curves, the stagnant temperatures for the mass feeding and interdendritic feeding during the solidification process of the alloy were determined as 420℃ and 390℃ respectively. By analysing the feeding conditions of upward continuous casting (UPCC) ZA27 alloy, a steady working condition was proposed under which the internal quality of the strand can be assured during UPCC.

Laser melting and subsequent heat-treatment have been used to modify the pearlite ductile iron coated with Buckytubes. The hardness of the samples can reach HRC65. Studies through SEM indicated that the main structures are martensite and net carbide. Meanwhile, the number of nodular graphite decreases obviously. Circular structures composed of martensite and carbide are found around nodular graphite. A new phase with regular shape has been observed. The new phase is devoid of Fe, Mn, Cr, Ni, Cu and its formation relates with the martensitic transformation.

Based on the high toughness mechanism, the relationships between heat treatment processes and the microstructure, fracture, characteristics, and mechanical properties at room and high temperatures of extrusion die steel 3Cr2W8V were studied. The results showed that by employing the process of super-high temperature quenching (over 1250℃) and medium temperature tempering (400-500℃), the extruion die steel 3Cr2W8V can obtained good comprehensive properties, including high toughness, thermo-strength, thermo-stability, thermal fatigue and abrasion resistance etc.

The crystal growth criterion was studied to obtain eutectic composite materials for hypoeutectic Al-Li alloy. It is shown that the solid/liquid interface exhibits a stable and planar form and the ragular eutectic structure can be obtained when 6.5×10~5 K·s·cm~(-2)≤ G_L/R< 11×10~5K·s·cm~(-2). The morphology of β phase (AlLi) is bar-like in Al-Li eutectic structure.

The model specimen of SiC_w/Al composite is subjected to the tensile test, simultaneously, the acoustic emission (AE) characteristics during the process of strain and fracture are monitered. The broken number of SiC fiber and the segment length of the broken fibers in the composite can be measared by AE technique. The interfacial shear strength and the fractural strength of fiber can be easily determined.

Acoustic emission(AE) behaviors of SiC_w /Al composites in which the surface of SiC fiber was and not treated by SiO_2 and C respectively, have been studied during tensile testing. The fiber strength and the interface shear strength between fiber and matrix have been measured by AE technique. It is found that the interface shear strength and the fiber fracture strength as well as the interface properties are sensitive to the surface treatments of fiber. The SiC_w / Al composite made of SiC treated by SiO_2 possesses the better interface properties, whereas, the composite made of SiC treated by C has the brittle interface.