Advanced Materials Research Vols. 146-147

Abstract: There is a comparison among the six Methylene Blue testing methods from different areas and institutes which respectively belong to China, U.S. and Britain. So as to improve the current MBV test of powdery lot used in asphalt mixture in China，it is found that current MBV test needs to be improved by analyzing powder lot Suspension、the concentration of Methylene Blue solution、stirring speed、powder lot types, temperature and soil content. So the revising suggestion to test method T0349-2005 included in standard JTG E42- 2005 is put forward. Later in the micro-surfacing test it is found that by adjusting the silt content, the water damage resistance and anti-abrasion abilities have been affected significantly which are good related to the MBV test recommended in this paper, so it is evident that the improved MBV test is crucial to the quality control over fine aggregates.

Abstract: Thermal oxidation tends to improve surface performance of titanium and its alloys by thickening the native passive oxide layer. In the present work, investigation of thermal oxidation in a wide range of treating temperatures between 500-850°C was carried out for commercially pure titanium (CP-Ti) to determine the optimum thermal oxidation parameters by evaluating the corrosion resistance. Characterization of modified surface layers was made by X-ray diffraction analysis and surface hardness measurements. The results showed that the rutile TiO2 layer was formed on the surface of specimens, and the thickness of the TiO2 layer and the surface hardness increased with the treating temperature. Evaluation of corrosion resistance indicated that the optimum thermal oxidizing temperature was 700°C under air atmosphere.

Abstract: Comparative research was done on the performance of new highly visible-light responsive photocatalyst Bi20TiO32 with P-25. Surface photovoltage spectrum of Bi20TiO32 indicates that its absorption wavelength starts from 550nm. Under Xe-lamp irradiation and the same catalyst dosage, the apparent rate constant of degrading methyl orange by P25 is 0.0465min-1, which is 2.7 times higher than that achieved by Bi20TiO32 (0.0172min-1). The apparent rate constant of degrading phenol by P-25 is 0.0543min-1, which is 1.8 times higher than that achieved by Bi20TiO32 (0.0296min-1). And the TOC removal of the solution by P-25 is also greater than by Bi20TiO32. But the performance of Bi20TiO32 under visible light irradiation is better than P-25. Under the visible light irradiation (>400nm), the apparent rate constant of degrading methyl orange by Bi20TiO32 is 0.0119min-1, which is 3.13 times higher than that achieved by P25 (0.0038min-1). The apparent rate constant of degrading phenol by Bi20TiO32 is 0.0133min-1, which is 33.25 times higher than that achieved by P-25 (0.0004min-1), and TOC removal by Bi20TiO32 is also much higher than by P-25.

Abstract: Basic on a lot of tests, the process of high temperature oxidation under tensile load had been experimentally researched on Cr5Mo alloy. The surface crack and the reaction rates and the shell of high temperature oxidation under tensile load or without tensile load also had been analyzed on Cr5Mo alloy, then the exactly research law of high temperature oxidation under tensile load had been gotten on Cr5Mo alloy in this paper.

Abstract: SEM observations of coir fiber microstructure have been carried out. Uneven surface characteristics are conducive to the bonding between coir fibers and resin materials. The unique advantages of coir fiber have been verified. Doing orthogonal experiment design for coir fiberboard, the coir fiberboard can meet the mechanical properties of National Standards of China. The various factors optimization plan on the performance of coir fiberboard has been obtained. FFT nondestructive testing has been done for the coir fiberboard. Nondestructive testing results show that the good correlation exists between dynamic mechanical properties and the static test results.

Abstract: The effect of temperature and strain rate on the mechanical behavior and microstructure evolution of Near Gamma Ti-46.5Al-2Nb-2Cr (NG TiAl) was investigated at temperatures ranging from room temperatures to 840 under strain rates of 0.001, 320, 800 and 1350s-1. The TEM analysis indicated that deformation twinning and stacking fault are the main deformation modes under dynamic loadings and dislocation slip is another important deformation mode under quasi-static loadings. The density of deformation twinning and/or stacking fault increases with the increased temperature and strain rate.

Abstract: Analysis on microstructure of semi-solid AZ31B magnesium alloy produced under different technological parameters were done, hot rolling experiments of AZ31B magnesium alloy semi-solid strips were carried out on the rheocasting-rolling machine which was developed by ourselves. The result shows that the strips after the rheocasting-rolling of AZ31B semi-solid magnesium alloy have good plasticity and rolling properties, this offers theory basis for reprocessing of AZ31B.

Abstract: The experiment of the rheocasting-rolling for semi-solid magnesium was carried out on the equipment made by ourselves in our laboratory. Semi-solid AZ91D magnesium slurry was prepared by cooling slope and the evolution of microstructure under different technological parameters such as pouring temperature, casting temperature, standing time, angle of slope and length of slope et al were studied. The results show that the technological parameters have great influence on the microstructure of the semi-solid magnesium slurry. The results show that the optimum parameters of slope method were: pouring temperature 630 degrees；angle of slope 60°；length of slope 0.570m.

Abstract: The problem that the pinch roll of the Slab Size Press was worn away partly appeared in some domestic steel mill so based on the DEFORM finite element software a pressing mode1 for Slab Sizing Press was established. After analyzing the deformation of dog bone by the modeling experiment finite element, a new kind of roll is brought forward. The contact condition between pinch roll and pressed slab is improved by it so that the use time of the pinch roll is extended.

Abstract: On the basis of MATLAB software，multi-fractal analysis program has been developed．Systematic fractal analysis of micrographs of TB8 alloy after hot compression deformation and solution treatment has been conducted．Corresponding probability measure and scale exponent from the microstructure images can be acquired and the multifractal spectra can be calculated．The results show that the microstructure of TB8 alloy after hot deformation and solution treatment has the characteristic of multi-fractal within the computing scale．And with increase of the recrystallized grain size and decrease of the deformed grain size，the width of the multi-fractal spectrum Δα decreases and the microstructure distribution is homogeneous．Furthermore，with increase of the recrystallization percent，the value between the maximum and minimum subset dimension Δf increases．It indicates that the recrystallized grains are the dominant factors in determining the size distribution in the microstructure and the grains are fine and uniform．These studies supply a new method for analyzing material microstructure quantitatively