Advanced Materials Research Vols. 194-196

Abstract: A novel filament winding process technology has been realized which allows to combine on-line solution impregnation with in-situ consolidation for a kind of high performance thermoplastic, poly (phthalazinone ether sulfone ketone) (PPESK). This technology solved the common problem of impregnating a large number of slender filaments with a highly viscous polymer melt which usually existed in thermoplastic manufacturing. During the winding process, the high-quality carbon prepreg tapes were firstly obtained on-line by using solution impregnation method, and then an arc electric heater was utilized to ensure the adaptable preheating and processing temperature. With the help of heat and tensile force, the intimate interlaminar contact was achieved.

Abstract: In the article, porous silicon carbide composite is prepared based on stereo lithography apparatus (SLA). The microstructure of porous silicon carbide composite is characterized by mean of scanning electron microscopy (SEM). The properties of porous silicon carbide composite are studied, such as surface HV and corrosion resistance, and the influence of the pore agent content to mechanical properties.

Abstract: The undoped and La-doped nanostructured Ag-SnO₂ coatings on pure copper substrate were prepared by supersonic plasma spraying. The phase compositions and microstructures of coatings were characterized and mechanical properties including micro-hardness and bonding strength of coatings were measured. Meanwhile, conductivity test was performed on the both Ag-SnO₂/Cu contact materials. Compared with undoped Ag-SnO₂ coating, La-doped Ag-SnO₂ coating exhibits the more dense structure with fewer pores, and show slightly higher micro-hardness and bonding strength. Doping La can effectively enhance the electrical conductivity of Ag-SnO₂/Cu contact materials.

Abstract: The 3D needled C/SiC composites were fabricated by chemical vapor infiltration combined with liquid melt infiltration. The microstructure and compressive behavior of 3D needled C/SiC composites were investigated. The results indicated that the 3D needled C/SiC composites were composed of the layers of 0 ° non-woven fiber cloth, short fiber web, 90 ° non-woven fiber cloth, and needle fibers. The materials were composed of carbon fiber, PyC, Si, and SiC. SiC and Si were mostly distributed in the short fiber web layers. Local C/C units (local carbon fiber reinforced PyC) were formed in the fiber bundles of non-woven fiber cloth. A great deal of pores and cracks existed in the 3D needled C/SiC composites. The pores less than 10 μm were generally located in the non-woven cloth layers, while the big pores were in the short fiber web layers. The cracks were regularly presented in the Si and SiC region of the composites and were normal to the axial direction of the fiber bundles. The compressive strengths perpendicular and parallel to the non-woven fiber cloth were about 118±18 MPa and 260±41 MPa, respectively. The compressive fractography revealed stepwise fracture along fiber layers direction.

Abstract: In this study, we prepared the 3-aminopropyltriethoxysilane (APTES) functionalized MWNTs/epoxy composites by electron beam (EB) irradiation process. The modified MWNTs were characterized with SEM-EDS and FTIR. The gel content and conversion rate of epoxide groups of the EB cured pure epoxy resin and the APTES functionalized MWNTs/epoxy composites were measured and discussed. And the mechanical properties of the EB cured composites were also characterized. With addition of 0.25wt% APTES functionalized MWNTs, the Vicker’s hardness of the EB cured composite increased 100.02% compared with pure epoxy.

Abstract: Stitched woven composite π joints and paralleled samples without stitching were investigated by numerical analysis under tensile loading. The effects of stitching on the mechanics behavior of composite π joints are presented. Stitching technique can reduce initial failure load of composite π joint, but remarkably improve the rupture load. The failure process of composite π joint, including the damage onset, propagation path and final failure pattern, is also limited in the stitched area. The failure mechanisms are expatiated by the numerical data and failure picture to obtain more knowledge about the mechanics behavior of composite π joints.

Abstract: Ti-Cu laminated composites were fabricated by means of vacuum hot pressing (VHP). The Ti-Cu interfacial reaction was studied to observe the microstructural changes. Scanning Electron Microscopy (SEM), Energy Disperse Spectroscopy (EDS) and X-Ray Diffraction (XRD) were used to observe morphology and analyze phase composition of interfacial reaction zones. With increasing the holding time, the thickness of the reaction zones varies from 12μm to 16μm. The results show that there are 5 binary intermetallic compounds (Cu₄Ti, Cu₄Ti₃, CuTi, Cu₃Ti₂, CuTi₂) observed in the Ti-Cu diffusion couples held at 1073 K for 1h, 1.5h, 2h and 2.5h respectively under the pressure of 10MPa.

Abstract: Gas diffusion layer is a very important component in fuel cell, and carbon fiber paper is widely used as substrate of gas diffusion layer. This paper has developed one way to produce carbon fiber paper from carbon fiber felt with or without pretreatment. The properties and microstructure of carbon fiber paper were also stdied. The results show that the pretreatment of carbon fiber felt is helpful to prepare carbon fiber paper with good properties. The content of carbon derived from resin during pretreatment has effects on density, thickness, porosity, gas permeability, porosity and tensile streagth of carbon fiber paper. Carbon fiber paper made from carbon fiber felt with pretreatment has better interface adhension than that of carbon fiber paper made from carbon fiber felt without pretreatment. Carbon fiber paper was produced with thickness of 0.28mm, density of 0.43g/cm³, porosity of 77%, gas permeability of 2500 mL•mm/(cm²•hr•mmAq), specific resistance of 0.017Ω•cm and tensile strength of 18MPa, which is a promising materials for fuel cell electrode.

Abstract: The geometric parameters of composite used in structure usually has the random properties. It is very significant for the reliability and optimization of structure design to research the random response and statistic characteristics of random parameters nonlinear systems. In this article, we use both of perturbation method and random central different approximation method to study the random response of random parameters nonlinear systems under uncertainty, get one kind of approximate iteration relationship of square response, and analyze the statistic characteristics of random parameters anti-symmetrically laminated plate.

Abstract: The methods of controlling Highway semi-rigid base asphalt pavement cracks and other diseases are always hot fields of road engineering and academic circles. The existing methods are on some degree efficient on delaying the formation and extension of cracks, but the effect is limited with different methods and various mechanisms of preventing cracks. Base on force analysis of pavement, this article presents a new technology of crack controlling which uses intelligent composite materials interlayer. By adding a stress absorbing layer between the asphalt surface layers or the semi-rigid base layers with low modulus, good toughness, self-adaptability and self-control ability, the intelligent composite materials interlayer has a good effect on controlling cracks which has been proved by the theoretical calculations and experimental analysis. As a result, the intelligent composite materials interlayer could efficiently prevent and delay the formation and extension of cracks, the safety and comfort of highway could be improved significantly while the cost of construction and maintenance decreasing. And the service level and social image of the road could also be improved effectively. This research has important academic and application value.