Advanced Materials Research Vols. 785-786

Abstract: Similar welds composed of 5083 were produced by friction stir welding. In the solution of 0.2 M NaHSO3 and 0.6 M NaCl, with the addition of a given concentration sodium molybdate as the inhibitor, the electrochemical corrosion behaviors of the friction stir welds (FSW) and 5083 were comparatively investigated by potentiodynamic polarization curve tests and electrochemical impedance spectra (EIS) for different test temperatures (herein, 25°C,30°C,35°C,40°C). The results indicated that at 30°C, the anti-corrosion property of 5083 FSW weld and parent material was superior to those of the other temperatures.

Abstract: It is shown that the process of-phase particles dissolution in the alloy matrix is faster at superplastic deformation than during annealing. Identify ways of 40CrNiAl alloy strengthening treatments after superplastic deformation were determined. Use after superplastic deformation re-quenching and aging leads to an effective hardening of 40CrNiAl alloy. In grains of-matrix allocated secondary lamellae of-phase intermittent mechanism.

Abstract: Synthesis of the series of compounds, which could be put into extract copper , contained hydroformylation, etherification, oximation. Resorcinol as the starting material was transformed to 2,4-dihydroxybenzaldehyde, and then converted to 2,4-dihydroxybenzaldehyde, which oximated to (E)-2-hydroxy-4-alkoxybenzaldehyde oxime.

Abstract: A kind of novel (E)-2-hydroxy 5-alkoxyl salicylaldoximes copper extractants was designed and synthesized. The synthetic route was started from 1, 4-dihydroxybenzene and the reaction sequence employed for the preparation of the (E)-2-hydroxy-5-alkoxyl salicylaldoxime included monoetherification, formylation and oximination.

Abstract: Extraction of vanadium has been developed to extract vanadium from hydrochloric solutions with high concentration of iron ions. The effects of extraction conditions such as pH values, extraction time and extraction temperature on the distribution ratio of vanadium were investigated. The results showed that the distribution ratio of vanadium increased with the higher pH, the lower temperature and the longer equilibrium time. The distribution ratio reached 25 and the extraction ratio reached 96.2% by single stage extraction. When the organic phase was stripped with 2 mol/L hydrochloric acid at the phase ratio (O/A) 10:1, the vanadium stripping ratio of 98.3% could be achieved.

Abstract: Polypropylene/organoclay modified by dodecanol phase change material were prepared by melt blending method. The thermal stability and crystallization behavior was studied by thermogravimetry (TG), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). TG results indicated the window of processing of PP could be improved by adding small amount organoclay modified by dodecanol to the blend. DSC showed the organoclay modified by dodecanol affected the crystallization behavior of PP as heterogeneous nucleation agent. XRD results show that the organoclay modified by dodecanol does not change the crystal structure in the blends but only decrease the intensity of the diffraction peak.

Abstract: Expansive soil has properties such as expanding when encountering water, shrinking and crazing when losing water. Mixing with certain proportion of cement is the main method to modify expansive soil now. According to the field modification experiment on expansive soil which has been done in 3^rd section of Changjiang-to-Hanjiang water diversion project, the paper researched the modification effect of different kind of expansive soil that modified by different cement proportion, and modification effect that depends on different size of broken soil mixed in the field. The experiment result shows that, for the medium and weak mixed expansive soil and medium expansive soil in study area, the optimal cement proportion is 4% and 6%. The free swelling ratio of mixed expansive soil can be decreased below 40% by any broken size, and the medium expansive soil can be modified effectively only when the biggest broken size is less than 31.5 mm by controlling the moisture content and improving mixing technology.

Abstract: Influence of different flame retardants on the heat release performance of the rigid polyurethane foam (RPF) was studied in this paper. It was found that adding antimony trioxide (ATT) in RPF, heat release rate of RPF was slightly reduced, total heat release was significantly decreased but peak of heat release temperature was decreased. Therefore, ATT was not an excellent flame retardant for RPF. When adding ammonium polyphosphate (APP) in RPF, total heat release of RPF was significantly decreased, ignition temperature was significantly improved and heat release rate was not changed. Melamine polyphosphate (MPOP) could quickly reduce total heat release of RPF so its flame retardant effect was the best. Nitrogen-based flame retardants could reduce peak of heat release rate of RPF. APP, MPOP and nitrogen-based flame retardants were all better flame retardants for RPF. Small amount of magnesium hydroxide (MH) could increase total heat release of RPF.

Abstract: Graphene/polyimide nanocomposites with different weight loadings were prepared by a solution compounding technique. Graphene was synthesized from graphite oxide that was fabricated by the Hummers method. X-ray diffraction (XRD), ultraviolet visible (UV-vis) spectra and simultaneous thermal analysis were used for the microstructure analysis of the graphenes. Graphenes with single layer structure were synthesized successfully and had good solubility in water or other polar solvents due to a few functional groups on the graphene carbons. Graphenes have good thermal stability. Mechanical and tribological properties were studied for the graphene/polyimide composites. The composites have excellent strength and toughness with very small graphene loading level and the addition of graphene decreased the friction coefficient and wear rate of the composites.

Abstract: To estimate the level of interfacial adhesion between the fiber and polymer-matrix in fiber/matrix composites, interfacial fracture toughness was derived based on an energy balance scheme. A break gap occurring at the initial interface debond during fragmentation test was taken into account. The external work and work done against friction slip at debonded interface were included in energy balance scheme. The interfacial fracture toughness obtained is a function of fiber and matrix material properties and critical debond strain which is the external strain applied on the specimen to initiate interfacial debonding. The break gap calculated increases with increasing applied load and decreasing friction coefficient. The proportion of each energy terms in energy balance equation was calculated. Comparison between the predicted interfacial fracture toughness and that numerical result was done.