Advanced Materials Research Vols. 239-242

Abstract: To refine thick and brittle needle-like or sheet-like iron-rich phase in Al-Fe-based alloy, electromagnetic cast and solid extrusion were adopted for the preparation of billet of rolled alloy Al-5%Fe-1.2%Si-1%Mg-0.6%Cu-0.5%Mn. Studies were made of the effect of rolling process on the microstructure and mechanical properties especially on the mechanical properties at high temperature. The hot deformation behavior of Al-Fe alloy was simulated at the strain rate of 0.01s-1 to 10s-1 and the temperature between 783K and 693K. The results indicate that there is significant steady-state rheological feature on the alloy’s high temperature deformation and the flow stress is sensitive to strain rate and temperature. The tensile strength of the alloy can reach 348MPa at 150°C and 170 MPa at 300°C but with a drop of around 40% than that at room temperature, indicating that heat resistance of the alloy is better at 150-200°C, the strength simulated long at 80°C can reach 275MPa, with rather good thermal stability.

Abstract: Poly (methyl methacrylate) (PMMA) sheets were radiated by ⁶⁰Co γ-ray in air and then irradiated PMMA foams were successfully prepared by supercritical CO₂ (SC CO₂) as a physical blowing agent via pressure quench method. The effects of radiation dose on the cell morphology and structure of the obtained foams were studied. The results showed that the foams possessed spherically closed cell structure with uniform cell size. The γ-ray irradiated PMMA sheets had a high cell density than those virgin PMMA.

Abstract: The desulfurization of high-sulfur diasporic bauxite （from China） with flotation process and ethyl thio carbamate as collector was studied, and the effects of flotation time, pulp density, pH value and particle size of ores were examined. The experimental results indicate that the sulfur in bauxite was successfully decreased through flotation. The sulfur content of bauxite was lowed to 0.66% under the condition of pH value 4, the dose of flotation agent ethyl thio carbamate 0.5kg/t, frother 20g/t, flotation time 15 minutes, pulp density 10%, the particle size of ores ≦0.09 mm, and the reclamation of Al₂O₃ is 90.16% as well. The flotation kinetics of flotation desulfurization was also studied.

Abstract: Biodegradable polyesters with free hydroxyl groups were synthesis by the lipase-catalyzed polycondensation of L-malic acid with different diacids (succinic acid, adipic acid and sebacic acid) and diols (ethandiol, 1,4-butanediol, 1,6-hexanediol and 1,8-octanediol). The molecular weight (Mw) of the copolymers was affected by the alkylene chain lengths of diacids and diols. It was found that diacids and diols with longer alkylene chain lengths have a higher reactivity than that of shorter chain-length diacids and diols. The crytallizability of the copolymers were affected by the alkylene chains length of diacids and diols. The crytallizability decreased with the decreasing of the alkylene chains length of diacids and diols.

Abstract: TiB₂ protective coating was prepared in the 310S container wall to improve the life of the container and achieve long-term protection purposes, and also studied the properties of TiB₂ coating with anti-heat shock, mechanical and anticorrosion to molten Al-12.07%Si . The results showed that the anti-heat shock properties of the coating was good, bonding strength between coating and substrate was high, the corrosion resistance was improved under certain limited temperature, and the life of container was also remarkable enhanced.

Abstract: The effects of external conditions such as short-circuit maching vacuum extraction,short-circuit maching gas carry or different applied voltage on the dehydrogenation by the hydrogen pump with CaZr_0.9In_0.1O_3-α electrolyte at 755°C in aluminum melt were studyed. Among the three external conditions,the dehydrogenation rate of hydrogen pump by applied voltage was fastest,followed by vacuum extraction,then gas carry while the effect of oxygen gas carry was better than the one of argon gas. When the pump was applied 1.5V,the hydrogen content in Al melt was reduced to 0.131ml/100gAl which met conventional aluminum alloys.

Abstract: A series of novel transparent hydrophobic regenerated cellulose (RC) films were coated with a fluorocarbon polymer by radio frequency magnetron sputtering. The effect of sputtering power and pressure on the surface morphology, chemical composition, contact angle and visible light transmittance of the coated films were investigated by atomic force microscopy, X-ray photoelectron spectroscopy, contact angles and ultraviolet-visible spectroscopy. The surface roughness increased as the sputtering power and pressure increased. The fluorocarbon coatings contained four components: -CF₃, -CF₂-, -CF- and -C-. The relative proportions of the saturated components significantly affected the hydrophobicity of the coatings. After applying a fluorocarbon coating, the static contact angle of the coatings was greater than 90°, and the substrate RC film was transformed from hydrophilic to hydrophobic. The visible light transmittance was greater than 80% when the roughness of the coating was less than 100 nm. The optimal sputtering conditions used a power between 80 and 150 W, and pressure between 1.0 and 3.0 Pa.

Abstract: removed at author request due to unrepeatable results

Abstract: A complicated auto panel forming is nonuniform plastic course and it is critical for dynamic reasonable the process parameters to avoid and decrease non-crackle, non-wrinkle, thickness uniformity forming defects. So, the forming of auto panel right beam is simulated by finite element software while the blank holder force and depth, die radius, punch radius of draw bead are independent variables, acquiring forming quality object (the data about the crack, winkle and the thinning)by orthogonal experiment. And the weight of multi-object is calculated by analytic hierarchy process, the grey relational generating and the grey rational grade of multi-objective are all calculated by the grey theory system while forming course is subdivision.Then, the dynamic optimization process parameters of blank holder force and draw bead restrain force are attained. Furthermore, employing the dynamic regulation-control optimization data to numerically simulate the auto panel forming. The conclusion demonstrates that the forming quality is obviously increased by the optimized process parameters.

Abstract: We report a facile and novel route to in-situ growth of conducting polypyrrole (PPy)/Fe₃O₄ nanocomposites via a counter-ion induced method, in which the cationic surfactant CTAB was used as a soft template, ammonium persulfate (APS) or FeCl₃ was used as an oxidant, and organic acids were used as a configuration “directing” agent. The as-synthesized nanocomposites were characterized by TEM, XRD and the measurements of their electromagnetic properties. Experimental results show that both the kind of oxidant and the size of counter-ions in the polymerization system play the key roles in the fabrication of the morphologies of the final PPy/Fe₃O₄ nanocomposites. A uniform core-shell spherical nanostructure was formed when FeCl₃ was used as the oxidant, whereas the string-bead nanostructure could be obtained when APS was used instead. The size of the counter-ions during the connection of micellar molecules could directly induce the formation of the PPy/Fe₃O₄ composites with various morphologies from spherical nanoparticles, nanofibers or string-bead nano-network to microtube structures. Meanwhile the loading amount of Fe₃O₄ ferrofluid would not only determine the diameter size of the string-bead nanostructures, but also the electromagnetic properties such as the microwave absorbing capacity of the resulting nanocomposites.