By using high energy ball-milling and vacuum hot-pressed sintering techniques, ultrafine grained carbide cement WC-2.5TiC-10Co were prepared, and the effect of grain growth inhibitors Cr₃C₂, VC, TaC and NbC on microstructures and mechanical properties were studied by X-ray diffractometer, field emission scanning electron microscope (FESEM) and mechanical performance test. The results indicates that the particle size of the WC powder can be reduced to less than 0.2 μm from 0.6 μm after 30 h of high energy ball-milling at a rotation speed of 350 r/min and ball/powder ratio of 10: 1. After vacuum hot-pressed sintering at 1410℃ for 1h, no new reactive product formed revealed by XRD. When 0.45 %Cr₃C₂, 0.3 %VC, 0.5 %TaC or NbC were added to the carbide cement, a small quantity of abnormally coarsened WC grains occurred, while the fractured surfaces display loose and smooth. Analyzing the fractured surfaces indicate that cleavage cracking in coarsened WC grains was caused by concentrated stress and become the source of materials fracture. When the contents of inhibitors Cr₃C₂ and VC were both more increased 0.1%, the grain size of WC can be reduced less than 0.5 μm. In such a case, the fractured surfaces are intimate and step-like, while the bending strength can be increased by 20%. Inhibitors TaC and NbC have not pronounced effect on the preventing the WC grain growth, while the addition of NbC is most effective in improving the relative density of the carbide cement.

Bimodal nanocrystalline (BNC) materials composed of coarse grains (CG) and nanocrystalline grains (NG), have both high strength and good ductility. In this paper, a new constitutive model was proposed by using Taylor strength theory and the Johnson-Cook modelto analyze the effect of grain size and nano-cracks on the constitutive/failure behavior of BNC materials. Numerical calculations have been carried out according to the model. It was found that the prediction result is in good agreement with experimental data. It can be concluded from the calculations that in BNC materials, (1) NC matrix can provide high strength, whereas CG can induce strain hardening to enhance its ductility, (2) the existence of nano-cracks does not lead to materials failure but a positive effect on strain hardening.

Anodic oxidation films of TiO₂ were prepared on titanium alloys Ti-6Al-4V(TC4) in an electrolyte system of oxalate, silicate and phosphate hybrid by means of anodic oxidation with TC4 as anode and stainless steel as cathode. Then the crystallographic structure, three-dimensional topography, microstructure and bioactivity of the prepared TiO₂ films were characterized by means of X-ray diffractometer, X-ray photoelectron spectroscopy, AFM and scanning electron microscope etc. The results show that the applied voltage has almost no effect on the crystal structure of TiO₂ films which are amorphous. There exist certain amount of pores and convex particles with ca.1.3 μm in diameter on the surface of rough TiO₂ film prepared by an applied voltage of 30 V. With the increasing applied voltage, the convex particles on TiO₂ films are slowly dismissed due to the field assisted dissolution. There are many nanopores of ca. 240 nm in diameter on the films without convex particles when the applied voltage is 100 V. There are many hydroxyls and micro/nano structures on the surface of anodic oxidation films on TC4 titanium alloy, which is useful for the enhancement of bioactivities and bone growth characteristics of the formed TiO₂ oxide films.

The waterborne epoxy coatings with polyaniline/vermiculite (PANI/VMT) as pigment were prepared. For the sake of identifying the functional groups of PANI/VMT, FT-IR measurement was performed. The thermal behavior of the pigments was characterized by thermal gravimetric analysis (TGA). The anticorrosion performance of waterborne epoxy coatings with different mass ratio of PANI/VMT was evaluated by electrochemical impedance spectroscopy (EIS) and salt spray test. The results show that a proper combination of the anodic protection ability of polyaniline and barrier property of vermiculite results in better performance of the PANI/VMT modified waterborne epoxy coating, for example, a coating with addition of 0.5% of PANI/VMT could provide a long-lasting anticorrosion protection for steel substrate.

Thin film of nanoporous Cu-Ti alloy as a promising electrode material for electrochemical capacitors was prepared by a two-step process, i.e. a thin film of Cu₃₅Ti₆₅ was firstly deposited on silicon substrate by magnetron sputtering process with Cu₄₀Ti₆₀ alloy as target , and then the sputtered film of Cu₃₅Ti₆₅ alloy was dealloyed in 0.13 mol/L HF solution for 12 h to prepair the isolated thin film of nanoporous Cu-Ti alloy. Electrodes made of the nanoporous Cu-Ti alloy exhibited excellent electrochemical capacitance performance with a specific capacitance of 8.96 mFcm^-2 in 1 mol/L Na₂SO₄ solution. Furthermore, the nanoporous Cu-Ti alloy electrode showed remarkable chemical stability by cyclically charging and discharging. The excellent electrochemical performance of the nanoporous Cu-Ti alloy can be ascribed to the high specific surface area of the nanoporous structure.

The meso-structure evolution of mortar may certainly induce a significant effect on its macroscopic mechanical properties. Herewith, the mechanism concerning the mechanical property degradation and the evolution of corrosion induced meso-structure damages of mortar were studied after immersion in different salt solutions. The experimental results show that after corrosion in salt solutions, the plastic deformation of mortar increased; and the stronger is the corrosion attack, the larger is the plastic deformation of the mortar; however which is an obvious time dependent process. Thus the degree of plastic deformation may be a reflection of the corrosion degree of mortar. A method based on nondestructive inspection was proposed to predict the variation of mortar porosity versus corrosion time, and then a new parameter for describing the damages was proposed . The present study revealed that after immersion in salt solutions the corrosion attack induced damage degree of mortar is closely related to its physical and mechanical parameters, which proves that the proposed method for quantitative analysis of the evolution of meso-structure damages is reasonable.

The edgewise compressive property of sandwich panel of steel plates with isosceles-trapezoid honeycomb core of fiber cloth reinforced epoxy resin is measured by using a material testing machine, while a simulation mode is established to describe the edgewise compressive behavior. The edgewise compressive pressure may induce three types of damages of the sandwich panel, namely, the broken of plates, the buckling instability of the sandwich panel and the detachment of plates with the honeycomb core. Under an applied edgewise compressive pressure, the plates are the main load bearing component of the sandwich panel, while the honeycomb core acts only as a connector and supporter . The parameter related with the structure and the material of the plates has a great influence on the in-panel compressive strength and the bearing stress for the sandwich panel. In the contrast, parameter related with the structure and the material of the honeycomb core has a small influence on the compressive strength of the sandwich panel, but the height of honeycomb core has a great influence on the bearing stress of the sandwich panel.

High temperature oxidation performance of ZG40Cr25Ni20 steel and a kind of low nickel austenitic heat resistant cast steel were comparatively investigated by means of isothermal oxidation test, scanning electron microscope(SEM) with energy dispersive spectrometry (EDS) and X-ray diffraction analysis. The results show that a protective oxide scale Cr₂O₃ forms at the interface of substrate and the outer oxide scale, which can certainly block the inward diffusion of oxygen ions and the outwards diffusion of metal action, thereby reducing the oxidation rate, therefore, the heat-resistant cast steel exhibits better high temperature oxidation resistance in comparison with the ZG40Cr25Ni20 steel, whilst the nickel saving steel contains lower Ni but a little higher Cr and Mn than the ZG40Cr25Ni20 steel.

Effect of the main TMCP parameters on mechanical properties and microstructure characteristics of X90 pipeline steel was investigated by a labroratory simulated TMPC with desired processing parameters, including reheating temperature, intermediate slab thickness and coiling temperature. Results show that the strength increases with the increment of reheating temperature at first, but dramatically reduces when the grain size gets coarse at reheating temperature of 1250℃. Thicker intermediate slab contributes to higher strength and toughness because of a homogenized microstructure with refined grains was brought out. Coiling temperature plays the most important role in controlling the steel property. A microstructure composed of proper combination of granular banite and lath banite of the steel with optimal matching of strength and toughness can be achieved when coiling at 320℃. An industrial production of X90 coil were carried out employing the parameters obtained through the investigation, high strength combined with great low temperature toughness has been achieved, which proves that TMCP technology in this study has a good practice effect.

Due to the complicated geometry and thin wall of the stainless steel impeller, during the investment casting process, some casting defects such as shrinkage porosity and filling shortage are usually produced, which have a close relationship with the filling and solidification process. So, the software ProCast was used to study the filling and solidification process of impeller and the numerical simulation results were compared with the experimental results in this paper. The following results can be acquired: 1. when the pouring temperature is 1550℃ and the casting speed is 0.75 m/s, the investment casting impeller can be filled to avoid the filling shortage defect; 2. although the appropriate pouring temperature and casting speed can avoid the filling shortage defect, but it can not avoid the shrinkage porosity defects in the impeller casting; 3. to pre-place certain cold iron in the middle of the impeller casting mold according to its structural characteristics can eliminate the shrinkage porosity defects. When the height of the pre-placed cold iron is 1/3 of the height of the inner cavity of impeller mold, the effectiveness in elimination the defects in the castings is the best thereby a high quality impeller can be acquired.