Advanced Materials Research Vols. 562-564

Abstract: Based on the discussion of the current research methods about the bi-stable composite shell, a novel experimental method named four points bending loading is presented to provide driving moments to snap an anti-symmetric bi-stable composite shell from one stable state to another. Then, the feasibility of this new method was confirmed using the finite element analysis software ABAQUS. Finally, the future work, which is to construct an experimental platform according the four points bending loading method, is pointed out.

Abstract: The fiber brakeage in compounding glass fiber-reinforced nylon-66 with different screw assemblies of the co-rotating twin screw extruder was studied, and comparative analysis of five different screw assemblies was made. The result shows that proper screw assembly could improve the residual fiber length and the mechanical property of the composite effectively

Abstract: Ultrasound treating system is used to improve, continuously and on-line, the wettability between carbon fiber and phenolic resin during the process of impregnation. The cavitation and the agitation action in the liquid aroused by ultrasound improve the adsorption, diffusion and wetting of phenolic resin on the surface of carbon fiber, enhance the mechanical properties and finally utilize fully the outstanding property of carbon fiber reinforced composites. Effects of ultrasound on natural properties of prepregs and surface morphology of carbon fiber/phenolic resin composites are studied. The difference of composite surface between not treated and after treated by ultrasound is watched by SEM.

Abstract: At present, most of cosmetic micro-needle in the market is made of biomedical stainless steels, but the processing technology is complicated and the piece-production cost is high. Micro injection molding technology can make the complicated polymer micro-needle in one cycle with the help of the rich experience accumulated in this area. And the method is suitable for mass production. This paper introduces the design of a new type of cosmetic micro-needle with polymer, its number simulation with injection molding software mold flow and the strength simulation.

Abstract: Three-dimensional braided composite materials for the use occurred during the fracture, deformation and other injury problems, a distributed Bragg grating sensor applied to detection of parts in health status. With three-dimensional braided composite weaving, research on the mechanical properties of small parts, sensors embedded in the sensor signal processing easy way. Embedded in three-dimensional composite parts of the sensor network signal processing method, the rapid implementation of distributed signal processing and the structure of large parts of the distributed monitoring.

Abstract: In this paper, aluminum nitride powder was prepared by carbothermal reduction. Alumina and carbon black powder were used as the starting material to synthesize aluminum nitride powder in a nitrogen atmosphere at 1500~1900°C. The experimental data, SEM photographs and XRD analysis showed that higher temperature was conducive to the increase in conversion ratio of Al2O3, the growth of particles, and improving the degree of crystallization and purity of AlN. But it made the particles’ size larger with poor dispersion.

Abstract: Single-phase β-Sialon ceramic compacts with z=2 have been synthesized by reaction-bonded sintering using Si, Al and Al2O3 as raw materials. After post-sintering at 1550°C for 2h, only β-Sialon ceramic compacts with z=2 was obtained. When the temperature up to 1650°C and 1750°C, the decomposition reaction of samples was occurred.

Abstract: A modified coaxial electrospinning process is developed for producing thinner methacrylate-based copolymer nanofibers. With Eudragit® L-100 (EL100) as a model and using a poor volatile solvent N, N-dimethylacetamide (DMAc) as sheath fluid, high quality EL100 nanofibers have been successfully generated using the developing coaxial process. SEM observations demonstrate that the nanofibers by the modified process have better quality than those produced by a single fluid electrospinning in terms of surface smoothness, nanofiber diameters and their distributions. The former has an average diameter of 240±30 nm while the later 490±170 nm. The mechanism is proposed that an appropriate DMAc surrounding to the core polymer jet helps to retain it in a fluid state to experience a longer time and more stable electrical drawing. The modified coaxial electrospinning process described here extends the capability of electrospinning process and opens a new way to obtain thinner polymer nanofibers with fine structural uniformity.

Abstract: Through the combined mechanical forces of sheer, friction and squeezing, the rigid polyurethane powder particles get certain plasticity. Based on the principles of mechanical and physical methods, an orthogonal test is designed, and then characterization analysis under conditions of different parameters is carried out through ATR-FTIR. The test indicates that when the rotate speed is 2400r/min, test time is 120min and inlet amount is 24g, the carbamic acid ester groups break down at the place of C-O bond and the cross-linked network structure is destroyed, then the best degradation effect is gained. This article provides theoretical basis for the recycle of thermosetting plastic.

Abstract: The directional solidification of the ternary Al alloy with composition of 2.6 at%Ni, 0.9 at%Y and 96.5 at% Al was carried out under the temperature gradient of 5 K/mm and the droping velocities of 0.5 mm/min, 1 mm/min, 5 mm/min, 10 mm/min, and 25 mm/min. The microstructure of the Al-Ni-Y ternary alloy was also analyzed by X-ray diffraction and optical microscope. The experimental results show that the microstructures of the Al-Ni-Y ternary alloy are consisted of ª-Al₂, Al₃Ni and Y₄Ni₆Al₂₃ phase when the alloy was directionally solidified in all directionally solidified rates in the experiments. No primary -Al can be found in the sample with directionally solidified rate of 0.5 mm/min. When the rates higher than 1 mm/min, the primary ª-Al can be observed. The microstructure of the directionally solidified alloy becomes finer and the primary ª-Al is smaller gradually with the increasing of growth velocities when the dropping rate of directional solidification is higher than 5 min/min. Two eutectic structures, Y₄Ni₆Al₂₃ andª-Al eutectic and Al3Ni and ª-Al eutectic, can be found when the dropping rate is higher than 10 mm/min.