Advanced Materials Research Vols. 490-495

Abstract: Nano-carbon materials were synthesized by catalytic decomposition of acetylene at low temperature 400 °C and 420 °C using iron supported on sodium chloride as catalyst. The samples were examined by X-ray diffraction, scanning electron microscopy and high resolution transmission electron microscopy. The results show that nano onion-like fullerenes encapsulating Fe cores with diameters in the range 20-50 nm were obtained when the reaction temperature was 400 °C and there were no carbon nanotubes in the product. These onion-like fullerenes are composed of concentric graphene layers with an interlayer distance of 0.348 nm between the layers. When the reaction temperature was 420 °C, carbon nanotubes with a structure of rope and low graphitization degree were obtained.

Abstract: Synthesis of onion-like fullerenes was carried out by chemical vapor deposition in a tubular furnace using iron catalyst supported on aluminum hydroxide at 400°C, 460°C, 600°C, 700°C, 800°C, 900°C and 1000°C, respectively, in the presence of argon as carrier gas and acetylene as the carbon source. The samples synthesized were characterized by high-resolution transmission electron microscopy, and the effects of temperature on the morphologies of the samples were investigated. The results show that the onion-like fullerenes prepared at the low temperature 400°C had the highest purity and good quality.

Abstract: AZ31 magnesium alloy sheets with a cross section of 5mm×50mm were prepared by semisolid metallic rheo-rolling device self-designed, and microstructure formation mechanism of AZ31 magnesium alloy during rheo-rolling was investigated. The results reveal that during the preparation of semisolid slurry, melt firstly nucleates heterogeneously on the surface of sloping plate. Under the vibration and shear of sloping plate, a relatively homogenous temperature field and composition filed are formed around some grains and are favorable for the direct growths of globular grains; meantime, dendrites formed under the vibration and shear are broken up and rounded gradually and better semisolid slurry is formed. During rheo-rolling, under the action of roll interfacial friction and rolling force, laminar flow shear inside the alloy is enhanced, and grains are further broken up and elongated. When the pouring temperature is 670°C, excellent AZ31 magnesium alloy sheet with good microstructure can be obtained.

Abstract: The hot deformation behavior of TC18 titanium alloy was studied in alpha-beta phase region. The temperature range was 1023-1123K and strain rate range 1-0.001-1s-1. The material constants of the alloy, including deformation activation energy ΔH as 364.823kJ / mol, stress-level coefficient α as 0.0086mm2/ N, stress exponential n as 3.8442 and structural factor A as 1.2601×1015s–1 were derived by Zener-Hollomon method from the interdependencies of flow stress, strain rate and temperature

Abstract: In order to solve the restoring problem of the high-strength steel accessories on the airplane, the feasibility study about restoring the high-strength steel accessories by electro-brush plating has been done. The restoring technics was discussed, furthermore, we test the rigidity, binding force and abrasion resistance of the parts after restoring. It indicates that the restoring technology owns many advantages, such as simple technology flow, convenient operation, low cost, strong binding force between the coating and substrate and good abrasion resistance, which could meet the request of the use completely. So it is worth extending.

Abstract: This paper mainly solved the 3D modeling and force analysis of φ320 mm hydraulic support column. According to the hydraulic support column standard, computer simulation was manipulated forφ320mm column by not only 1.5 times rated axis load strength analysis but also 1.1 times rated load and eccentric 30mm buckling analysis. Through analysis and simulation tests，not only the distribution and deformation ofφ320mm column but also the stress distribution and simulation conditions were got about column. Thus, theoretical basis could be provided for the design of column.

Abstract: The mixing process of composite solid propellant slurry in kneading mixers is considered as the research object. POLYFLOW software is employed to solve the problems numerically. Turning the mixing tank instead of the revolution of the impellers, thus the planetary motion is carried out only by the autorotation of the impellers around their own axes. With mesh superposition technique and mesh refinement technique, the impellers and mixing tank are meshed. Visualization of flow process and flow pattern in a kneading mixer is realized and flow fields of velocity, shear stress, viscosity and mixing index are obtained.

Abstract: In this paper, a phase field model based on Ginzburg-Landau theory is used to analyze the topological phenomena during grain growth. The simulation results show that two topological transformations exist during the grain growth—Neighbor Switching and Grain Annihilation; and we have found different kinds of topological events during the disappearance of a grain: direct vanishing of trilateral grain and pentagonal grain, as well as neighbor switching，which are right with classical topological theory and Euler formula. The simulation results are similar with experiments.

Abstract: This paper discusses lithium iron phosphate ion/li-ion polymer battery charge information integrated system, the balance of battery management information system and battery management information system. Finally the integrated system software is given

Abstract: Two gray cast irons with equal tensile strength were prepared to investigate the influence of alloying on the machinability of gray iron. After 75SiFe modifying treatment, they were alloyed by the mixture additive containing RE, Cr, Mn, Si and Fe with a certain proportion and pure copper, respectively. The hardness, section sensitivity, structuralhomogenity and machinability were tested in this experiment. The results show that both of the gray irons have the same brinell hardness and the micro-hardness. The section sensitivity of the gray iron alloyed by the mixture additive is smaller than the gray iron alloyed by copper. The main cutting force of the cast iron alloyed by the mixture additive is lower than that of the cast iron alloyed by copper, therefore, the gray cast iron alloyed by the mixture additive has a better machinability than the cast iron alloyed by copper.