The 20Cr1Mo1VTiB bolt steel was aged at 500℃ for 0~2000 h and then the effect of long-term aging on microstructure and mechanical properties were investigated by means of TEM, SEM, XRD, tensile- and impact-tester. Results show that the lath bainite in the steel was divided into several packets during the aging process. The size of the bainite package in the steel decreased from 13 μm before aging to 9 μm after aged for 2000 h. The main precipitates VC and TiC in the steel dispersed in the intragranular, lath boundaries and inside lath bainite after the aging process. TiC changed from a long strip to a square shape with an extension of the aging time. The boundary of bainite slabs gradually blurred with the increase of aging time, and the width of lath increased obviously after 2000 h aging. After aging for 2000 h the 20Cr1Mo1VTiB bolt steel still has high strength and toughness, therefore, which is suitable for long term service at high temperature.

In order to investigate the evolution of spinodal decomposition during ageing and annealing, a phase-field model based on Cahn-Hilliard equation has been developed to simulate the microstructure evolution in ferrite of Fe-Cr-Ni stainless steels. The simulation results reveal the formation of inter-connected α' phase during thermal ageing, and the increase of wavelength and amplitude of Cr concentration fluctuation with ageing time. During the subsequent annealing treatment, it is found that α' phase dissolves into the matrix, and the wavelength continues to increase, while the amplitude starts to decrease. The simulation results also indicate that the nano-indentation hardness is positively associated with the amplitude of concentration fluctuation. And the annealing time needed for recovery of spinodal decomposition (dissolving of α' phase) is reduced by increasing annealing temperature remarkably. There is an Arrhenius-type relation between the recovery time and the annealing temperature.

The quenching sensitivity of 6082 Al-alloy used in rail transit was investigated systematically by means of Jominy end-quench (JEQ) test, JMatpro7.0 simulation software, hardness test, tensile test and TEM. Results show that (1) The quenching sensitive temperature range is between 220~425℃. The nasal tip temperature for β'- and β''-phase is 375℃. According to the CCT curve, in order to suppress the precipitation of metastable β'- phase the cooling rate should be greater than 6℃/s during quenching process; (2) The hardness and strength decreased with the increase of the distance from the quenched end, and the depth of aging hardening layer is about 23 mm; (3) the quench-induced β-precipitates preferentially precipitated and grown on the heterogeneous nucleation site of α-(AlMnFeSi) phase, with the decrease of quenching cooling rate. During the subsequent aging process, the β-phase grows and absorbs the surrounding solute atoms, the strengthening precipitated β''-phase is reduced; (4) During the slow cooling process, the vacancy concentration near the grain boundaries decreases, and the precipitationfree precipitation zone (PFZ) at the grain boundaries widens.

Graphene oxide (GO) modified epoxy thermal insulation coatings were prepared by adding GO concentrates, then corrosion immersion test in 3.5%NaCl (mass fraction) solution at 50^oC and thermal insulation effect before and after corrosion tests were comparatively measured. Electrochemical analysis shows that the coating modified with 0.5% GO has higher low-frequency resistance than that of coatings with 0% and 1.0% GO. Good surface morphologies were retained for coatings with GO addition after immersion in 3.5% NaCl solution (50^oC) for 432 h. Meanwhile, no obvious cracks and corrosion products were detected on the coating/substrate interface. The coating without GO addition emerges obvious corrosion. The thermal insulation effect to a 250^oC heat source of the above three coatings before corrosion test presents slight differences. Whereas, after 432 h corrosion immersion test the coating with 0% GO, 0.5% GO and 1.0% GO presents quite different in thermal insulation effect with temperature drop as 98^oC, 123^oC and 115^oC for the coated substrate and decrease of bonding strength to the substrate as 3.9 MPa, 1.0 MPa, 2.3 MPa respectively. These results verify that the epoxy coating modified with 0.5% GO has the best corrosion resistance and thermal insulation performance.

Mesostructured metal-organic framework material MIL-53(Al)-F127 was synthesized by one-step solvothermal method, and the morphology and structure of MIL-53(Al)-F127 were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD), Fourier-transform infrared spectrometer (FTIR) and N₂ adsorption-desorption (BET). The adsorption performance of MIL-53(Al)-F127 and the microporous structure MIL-53(Al) on bisphenol A in aqueous solution and the influence of the adsorbent concentration, pH, temperature were comparatively investigated. Results show that MIL-53(Al)-F127 exhibited good adsorption properties for bisphenol A in aqueous solution. The optimum pH level for the removal of BPA using MIL-53(Al)-F127 were 6. The optimum temperature for the sorption behavior of BPA on the sorbent was 30℃. The equilibrium sorption amounts of BPA on MIL-53-(Al)-F127 reached approximately 27.2 mg/g, the removal efficiency was 92% after approximately 20 min. The sorption kinetics of BPA were found to follow the quasi second order dynamic model.

Co-continuous phase composite of SiC foam ceramic/ductile iron (DI) (SiC_foam/DI) was prepared by extrusion casting with the oxidized SiC foam ceramic as reinforcer, while the bare DI and composite of SiC_particles/ID were taken as comparison. The gas-solid two-phase flow induced erosion behavior of the three materials was assessed via a home-made gas-solid two-phase flow erosion tester, so that to reveal the effect of the erosion time (t), particle velocity (ν) and erosion angle (α), as well as the relevant erosion mechanisms. The results show that with the increasing erosion time, the erosion rate of the three materials decreased gradually and then down to a stable level. With the increase of particle impact velocity the erosion rate of DI increased gradually, and the erosion rate is proportional to ν^2.95. While composites of SiC_Particles/DI and SiC_foam/DI had similar erosion rates when the impact velocity was less than 87.5 m/s. When the impact velocity was greater than 87.5 m/s, the erosion rate of SiC_Particles/DI was significantly higher than that of SiC_foam/DI. With the increase of erosion angle, DI exhibited erosion characteristics of brittle material, but SiC_Particles/DI and SiC_foam/DI composites exhibited typical erosion characteristics of plastic material. The maximum erosion rate corresponded to the erosion angle 45°. The erosion mechanism of DI was micro-cutting at low angle, while erosion pitting and micro-cracking at high angle. For high-speed particle impact, SiC_foam/DI composite had better erosion- and wear-resistance than that of SiC_Particles/DI composite and DI due to the overall reinforcement and shadow protection of SiC foam ceramics.

Metallic tailings built glass-ceramics were prepared with Bayan-Obo tailings as the main raw material and Cr₂O₃ as nucleating agent. The crystallization characteristics of tailings built glass-ceramics were characterized by means of DSC, XRD, SEM and Raman spectra and the properties of glass-ceramics were evaluated by bending strength, Vickers hardness and acid resistance tests. Results show that the glass-ceramics are mainly composed of crystalline phases of diopside and gehlenite, while the nucleating agent of Cr₂O₃ can promote the precipitation of the main crystalline phase of diopside by forming spinel. The mechanical and corrosion resistance characteristics of glass-ceramics showed a decreasing trend with the increase of tailings content. The higher CaO content caused by the increase of tailings content can lead to the obstruction of sliding and migration of crystalline phases in the crystal growth process. As a result, it was easy to produce cavities and defects in glass-ceramics. Meanwhile, the increase of the ratio of gehlenite/diopside was not conducive to the improvement of the properties of the glass-ceramics. In addition, the rare earth elements intergrowth in Bayan-Obo tailings can form the second phase of cerium calcium silica at the grain boundary, which can reduce the area and the total energy of grain boundaries, which was helpful to improve the mechanical and corrosion resistance of glass-ceramics.

Ultrathin tetrahedral amorphous carbon (ta-C) films with different film thickness were prepared by filtered cathodic vacuum arc technique. The accurate measurement of the film thickness and sp³C content of the ultrathin ta-C films was conducted by means of ellipsometry combined with spectrophotometry. The acquired film thickness was further verified by XRD. The film density was acquired from the results of precise determination of lattice parameters. Raman spectroscopy were conducted to characterize the atomic bond structure of as-prepared film. The residual stress was calculated from the curvature of the film/substrate composite using Stoney^，s equation. Results show that as the film thickness increased from 7.6 to 33.0 nm there was no obvious change of the ultrathin ta-C film growth rate, which keeps constant as 1.7±0.1 nm/min, while the residual compressive stress and sp³ fraction decreased; for the film of thickness 7.6 nm the maximal sp³ fraction was obtained. The results are consistent with Raman's. For the film of thickness 11.0 nm, the maximal bulk layer density was 3070 kg/m³. The film thickness had no obvious influence on surface roughness of ultrathin ta-C films. In summary, ellipsometry combined with spectrophotometry is of feasible means for characterizing the structure and thickness of the ultrathin ta-C films. X-ray reflection can be used to measure the density and surface roughness of ultrathin ta-C carbon films of high quality.

The precursor of TiNb₂O₇ is prepared via solid-phase synthesis with anatase and Nb₂O₅ as raw materials and then calcinated at 400℃, 800℃, 900℃, 1000℃ and 1100℃ respectively in air to prepare TiNb₂O₇ as electrode materials. The prepared materials are characterized by means of thermo-gravimetric analyzer, differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical test. The results show that the main reaction products of anatase and Nb₂O₅ at 900℃ is Ti₂Nb₁₀O₂₉. TiNb₂O₇ is obtained by the reaction of Ti₂Nb₁₀O₂₉ and rutile. The optimum calcination condition of pure monoclinic TiNb₂O₇ is 1100℃ for 8 h. TiNb₂O₇ anode material has an initial capacity of 278.4 mAh/g at 0.2C and the initial coulombic efficiency is 82.9%. In the meantime, TiNb₂O₇ has a good rate capacity, which can still reach 89% after 100 cycles at 1C rate.

In order to improve the quality of cathode copper, the intense magnetic field was used to enhance the diffusion of Cu²⁺ and the self-purification process of copper electrolysis. From the point of view of ionic magnetism and ionic hydration, experiments on magnetized copper electrolysis at different flow velocity were carried out. The effect of Lorentz force and magnetic field gradient force on the diffusion properties, impurity ion concentration and apparent quality of cathode copper was investigated. The mechanism of copper electrolysis strengthened by vertical orientation magnetic field and horizontal orientation magnetic field was respectively analyzed. Results show that magnetic field can strengthen the convection, weaken the hydrogen bonding, reduce the ion hydration and increase the energy of the system. Besides, the diffusion of Cu²⁺ and the deposition rate of impurity ions such as As, Sb and Bi were also increased, which could improve the clarity of electrolyte and the apparent quality of cathode copper. On the other hand, the dissolved oxygen, microbubbles and surface tension of electrolyte increased with the increase of cyclical flow velocity, so leading to the failure of magnetic field synergy. There is an optimum cyclical velocity to improve the quality of cathode copper in the process of magnetized copper electrolysis.