Chemical oxidation and plasma polymerization were employed to functionalize the surfaces of multi-wall carbon nanotubes (MWCNTs). Then MWCNTs reinforced cyanate ester/epoxy resin nanocomposites were manufactured. The effect of the two functionalization processes on mechanical properties of the nanocomposite was investigated in terms of tensile test at room and cryogenic temperatures and observation of their fracture surfaces with SEM. Results show that the plasma polymerized MWCNTs (plasma-MWCNTs) may be dispersed more homogenously in the matrix and possess stronger interfacial bonding with the resin in comparison with the chemical oxidized ones. With addition of 0.3%(mass fraction) plasma-MWCNTs, the tensile strength, tensile modulus and impact strength of nanocompoistes at room and cryogenic temperature were simultaneously improved compared with the pure cyanate ester/epoxy resin matrix.

Tantalum carbide gradient composite was fabricated via in-situ reaction of pure tantalum plate with gray cast at high temperature. The morphology, phase constituent, microhardness, and relative abrasion resistance of the composite were characterized by scanning electron microscopy, X-ray diffraction, microhardness tester and abrasive wear testing machine. The results show that the thickness of the gradient composite is about 475 μm. The cast 170 μm thick surface layer is a dense ceramic layer consisted of ~95% submicron TaC particles, and the highest micro-hardness value of which is 2328HV_0.1; In the sub-layer, there exists a gradient distribution of TaC particles from 90% to 0% in volume fraction, correspondingly the microhardness value decreased from 915HV_0.1 to 410HV_0.1, and the size of the TaC particles increased to 0.5-1.5 μm; the interface between the composite and matrix exhibits a perfect metallurgical bonding. The TaC reinforced iron matrix surface gradient composite shows far superior wear resistance than the gray cast iron. The wear mechanism is mainly related with the local plastic deformation, micro cracking caused by misrouted broken carbide particles.

A carbon fiber reinforced polyimide composite material (CF/PI) was prepared by compression molding. Then the effect of carbonization treatment on the change of structure and property of CF/PI was studied. The results show that the weight loss of CF/PI is obvious during carbonization treatment at temperature from 500℃ to 800℃, implying the occurrence of the rupture of imides rings along C-N bonds, i.e. reactions of dehydroxylation and dehydrogenation occur successively. After carbonization, molecules of CF/PI are in a state of disorder, thus its mechanical performance falls sharply; at temperature from 800℃ to 1000℃, with the recombination of functional groups within molecules, carbon layer structure forms gradually in the composite, while the characteristic diffraction peak (110) of carbon may be detected and correspondingly the mechanical strength reaches the maximum for the composite carburized at 900^oC. The interfacial bond of the composite is enhanced with the increasing carbonization temperature, which is resulted from the heat activated interaction of polyimide with carbon fiber. The best comprehensive performance can be obtained for the CF/PI after carbonization treatment at 900℃.

The effect of Gd addition on the evolution of microstructure and mechanical properties of wrought AZ31 magnesium alloys was investigated. The results show that the added Gd reacts with other elements to form Al₂Gd and Al-Mn-Gd phase, leading to a reduction of β-Mg₁₇Al₁₂; for the as-cast alloy, a small amount of Gd addition weakens the grain refinement effect of Al and coarsens the grain size, then with the increasing amount of Gd addition, the grain size is reduced; for the rolled alloys, Al₂Gd can promote the dynamic recrystallization during the rolling process, which may result in the reducing of the number of twins, the weakening of the role of work hardening and the refining of grain size. However, an excess of Gd addition may induce the coarsening of second phase as well as the microstructure of the alloys. Therefore an appropriate amount of Gd addition can increase the elongation, while reduce the strength of the rolled AZ31 alloys. An optimal elongation 13.4% can be measured for the rolled AZ31-0.8Gd at 350℃, in the contrast, only 5.4% for the AZ31 without Gd addition.

A319 alloy with different secondary dendrite arm spacing (SDAS) was prepared by cutting samples from the cast ingot where locates at different distance from the bottom of the mold. The relationship between SDAS and porosity size, along with the relationship between SDAS and the ratio of size to aspect ratio of Si particles were investigated. Effects of SDAS on tensile properties, fatigue life and fatigue parameters were discussed. The results show that there is a linear relation between the ratio of size to aspect ratio of Si particles and SDAS. When SDAS is larger, Si particle size and the ratio of size to aspect ratio of Si particles, as well as porosity size are larger. SDAS almost had little effect on Young’s modulus and yield strength, while with the increasing SDAS, the tensile strength, elongation and hardness all decrease. Furthermore, with the increasing SDAS, the fatigue life and fatigue parameters such as fatigue strength coefficient ( b 0 ), fatigue ductile coefficient ( σ ′ f ) and fatigue ductile exponent ( ε ′ f ) all decrease, but as an exception, fatigue strength exponent ( c 0 ) increase.

The composition characteristics of reduced activation ferritic/martensitic (RAFM) steels were investigated using a cluster-plus-glue-atom model. The basic cluster formula [Cr-Fe₁₄](Cr_0.5Fe_0.5) was determined, where the cluster part [Cr-Fe₁₄] is a rhombic dodecahedron centered by Cr and surrounded by 14 Fe atoms. According to the principle related with self-consistent magnification of cluster formula and similar element substitution, two multi-component alloys were designed by adding V, Mn, Mo, W, Nb and C into [Cr-Fe₁₄](Cr_0.5Fe_0.5) i.e.[Cr₁₆Fe₂₂₄](Cr₈(V, Nb, Mn, Mo, W, Fe)₈) and {[Cr₁₆Fe₂₂₄](Cr₈(V, Nb, Mn, Mo, W, Fe)₈)}C₁. Alloy rods with a diameter of 6 mm were prepared by copper mould suction casting method, then normalized at 1323 K for 0.5 h and tempered at 1023 K for 1 h, both followed by water-quenching. The experimental results revealed that the substitutional solid solution alloys without C exhibit a monolithic ferrite microstructure and that of the other serial alloys with C varies with alloying elements and their contents. The microhardness (HV) of alloys changes with microstructures, and furthermore, while the HV of substitutional solid solution alloys decreases monotonously with the increase of the valence electron concentration per volume VEC/R_a³.

X-ray photoelectron spectroscopy (XPS) was used to characterize the surface films formed on Nb-60Ta-2Zr alloy with an immersion in simulated plasma solution (r-SBF) and human whole blood. Significant difference in the chemical composition and thickness of the oxide films formed on the alloy immersed in these two media was identified. After immersion in r-SBF solution for 24 h, an oxide film of mixed Nb₂O₅ and Ta₂O₅ formed on the alloy surface, while on top of which a 50 nm thick deposition film containing Ca and P could be clearly detected. In contrast, for the alloy immersed in whole blood, only a 24 nm thick oxide film of mixed Nb₂O₅ and Ta₂O₅ existed, but no deposition film containing Ca and P was detected. It was indicated that even though the ion concentration in these two media is nearly identical, the organic components in human blood such as proteins and blood cells may play a role to inhibit the deposition of Ca and P elements.

Ti-based anodes with a top layer RuO₂-TiO₂ oxides mixture and an inter-layer TiB₂ were prepared by two step processes, i.e. first the TiB₂ film was deposited on Ti-based anodes by means of magnetron sputtering and then the top layer RuO₂-TiO₂ oxides mixture was further deposited by a thermal decomposition process. The microstructure and phase constituent of the coatings were characterized by means of SEM and XRD, and the electrochemical properties of the anodes were evaluated by the polarization curves. The results show that the interlayer TiB₂ plays important role in suppressing the formation of the cross cracks of the RuO₂-TiO₂ layer and, facilitating the adhesion of the top layer to the substrate, therefore the RuO₂-TiO₂ and TiB₂ coated Ti-anodes exhibit better electrocatalytic properties rather than the only RuO₂-TiO₂ coated ones. In the meanwhile, the TiB₂ interlayer can suppress the occurrence of a TiO₂ film at the interface coating/substrate thus prolongs the life time of Ti-anodes. Besides, the inducing of the TiB₂ interlayer can reduce the potential of chlorine evolution, and thereby enhance the current efficiency of the Ti-anodes effectively.

Microstructure and texture of the as-drawn and the as annealed pearlitic steel wires were characterized by using SEM ( scanning electron microscopy) and EBSD ( electron backscatter diffraction) to reveal the effect of austenitizing process on the texture redistribution of the cold drawn pearlitic steel wire. The results show that the lamellar structure of the as-drawn pearlite steel wire turns to parallel to the drawing direction, forming ferrite <110> fiber texture. The intensity of the <110> texture rises with the rising strain of steel wires. After austenitizing heat treatment, the ferrite <110> fiber texture still remains in the wire, of which the intensity corresponds to the strain value of the as drawn wire. With the increasing of austenitizing temperature and time, the intensity of the ferrite <110> texture decreases. The ferrite <110> texture remains in the wire which has been cold drawn up to a strain value 2.2 and then annealed at 850℃ for 80 min.

Surface composites of WC reinforced steel matrix were fabricated by vacuum-expendable pattern casting (V-EPC) technology in order to provide theoretic direction for designing surface composites with high thermal fatigue performance, and then the thermo-physical properties of the composites, such as thermal expansion coefficients and thermal conductivities were characterized. The influence of process parameters on the thermo-physical characteristics was investigated. The results show that the thermal expansion coefficient the sampled layer decreased when the distance of which to the transition layer becomes lager. For the layers sampled at the same distance, their thermal expansion coefficient increased with the increase of WC particles size. For the surface composites reinforced with different sizes of WC particles, the thermal conductivities increased with the increasing temperature. When the temperature was higher (above 170℃), the thermal conductivities of the composites decreased with increase of the sizes of WC particles, and when the temperature was lower (40℃ and 105℃), the thermal conductivities of the composites did not change remarkably. The composite with Ni addition has lower thermal expansion coefficient and thermal conductivity than that of those without Ni.

The hot corrosion behavior of modified and conventional Thermo-Span alloys in 75%Na₂SO₄+25%NaCl molten salt at 650℃ for 100h was investigated by means of thermogravimetry (TG) and scanning electron microscopy equipped with energy dispersive X-ray Spectrum (EDS). The results show that the corrosion product consisted of oxides and sulfides exhibits a three layered structure: the external layer consists of Fe、Co and Cr oxides, in addition, Al and Co oxides also exist in this layer of the modified alloy; the intermediate layer is mixed oxides composed of Al、Cr and Ni and sulfides formed in the inner layer consisted of Ni and Co, the inner sulfidation layer in standard alloy is thicker than that in the modified alloy. For the modified alloy with higher Al addition, an aluminum rich oxide scale can form at the interface oxide scale/substrate , which can block the outwards diffusion of Fe and Co, and the inwards diffusion of O and S elements hence enhanced the hot corrosion resistance of the modified Thermo-Span alloy .

Fe³⁺and Gd³⁺ co-doped TiO₂ catalyst (Fe³⁺/Gd³⁺/TiO₂) and (Fe³⁺/Gd³⁺/TiO₂) finished SiO₂ catalyst (Fe³⁺/Gd³⁺/TiO₂-SiO₂) were synthesized by sol-gel method, and then characterized by XRD , SEM and DRS. The effect of processing parameters on their photocatalytic activity was investigated by measuring the effectiveness of the catalysts for degradation of nitrite. The results show that (Fe³⁺/Gd³⁺/TiO₂-SiO₂) possesses significantly higher photocatalytic activity rather than (Fe³⁺/Gd³⁺/TiO₂). A dose 1.0 g/L of the catalyst (Fe³⁺/Gd³⁺/TiO₂-SiO₂), which has been calcinated at 500^oC for 2 h and aged for 1 h, exhibits an optimal photocatalytic activity i.e. a degradation efficiency 90.46% for nitrite.