Advanced Materials Research Vol. 413

Abstract: The crystallization kinetics of amorphous alloy Mg₆₅Cu₁₅Ag₁₀Y₁₀ has been studied by differential scanning calorimetry in the mode of continuous heating annealing. It is found that both DSC curves and activation energy show a strong dependence on the heating rate. The activation energy for crystallization are determined as 186.1 and 184.4 KJ mol⁻¹ for the heating rates β=5-20 Kmin⁻¹, and 107.5 and 110.0 KJmol⁻¹ for the heating rates β=20-80Kmin⁻¹, when using the Kissinger equation and the Ozawa equation, respectively. Local activation energy at any volume fraction crystallized was obtained by the general Ozawa's isoconversional method. The average value of local activation energy for heating rates ranging from 5 to 20Kmin⁻¹ is 180.9 KJ mol⁻¹ and for heating rates ranging between 20 and 80Kmin⁻¹ is 110.2 KJ mol⁻¹. Using the Suriñach curve fitting procedure, the kinetics mode was specified. The JMA kinetics is manifested as a rule in the early stages of the crystallization. The JMA exponent, n, initially being larger than 4 and continuously decreases to about 2 along with the development of crystallization. The NGG-like mode dominates in the advanced stages of the transformation. These two modes are mutually independent. The proportion between the JMA-like and the NGG-like modes is related to the heating rate.

Abstract: Titanium alloy TC1 and Aluminum alloy LF6 were butt jointed by friction stir welding (FSW) using zinc as the middle layer material. Influence of zinc on the microstructure and brittle phases were studied. The results show that, the microstructure of the nuclear zone is a mixture structure with Ti alloy particles distributed on Al alloy substrate. At the same time, XRD test results show that there TiAl₃ intermetallic compounds and Zn_0.69Ti_0.31 intermetallic compounds in the nuclear region. The joint which is added zinc as the middle layer material becomes more brittle.

Abstract: For predicting the forward slip coefficient and veocity of outgoing workpiece exactly during alloyed bar rolling by Round-Oval-Round pass sequence, the influence of the spred of the outgoing workpiece and its contact boundary condition was considered and the calculating formula for the effective height of outgoing workpiece and the mean roll radius was proposed individually. Moreover, the new parameters were substituted into the Shinokura and Takai Formula to modify it. Then a modified forward slip coefficient firmula was proposed. The validity of the theoretical model has been examined by the bar rolling experiment and the numerical simulation using three-dimensional rigid-plastic FEM. Compared with the Shinokura and Takai dormula, the predict accuracy of the modified formula was improved apparently. So, it can be applied in alloyed bar rolling to predict the the forward slip coefficient and veocity of outgoing workpiece exactly.

Abstract: A new type compatibilizer-boric acid ester with carboxylic acid functional groups (refered as B) was synthesized and used in PPO/PA66 alloys. The PPO/PA66 alloys were produced by melting blending. The micromorphological and mechanical properties of PPO/PA66 blends with different contents of the compatibilizer were studied by transmission electron microscope (TEM), scanning electron microscope (SEM) and mechanical test. The effects of the compatibilizer B on the mechanical property and morphology of PPO/PA alloy were discussed. The results showed that, the compatibilizer B can also improve the mechanical property, besides showing good effect on the compatibility improvement for PPO/PA blends; it (B) acts as a compatibilizer for the blends by forming interim layer with dispersed phase PPO and continuous phase PA. The compatibilization of PPO and PA66 alloy was due to the chemical reaction between carboxyl group and amine group.

Abstract: The surrounding rock pressure which was determined effectively through in-situ monitoring was the important parametric of the tunnel engineering design.According to in-situ monitoring of the surrounding rock pressure in the relied engineering . The adjustment and distribution characteristics of surrounding rock pressure of the shallow large-span tunnel with three-level seven-step parallel tunnel excavation was studied, the results showed that the arch and sides of the tunnel arch foot were the key parts which concentrated the surrounding rock pressure. The adjustment and distribution of surrounding rock pressure had not obvious relationships with tunnel face distance. Finally, the composite factors that impacted monitoring results of the surrounding rock pressure was analysed. The results had great significance on the development and perfection of the surrounding rock pressure theory in shallow large-span tunnel.

Abstract: Acetyl ferrocene hydrazine hydrazone and its novel metal complexes were synthesized. The structures were confirmed by elemental analysis, IR, molar conductance and thermo gravimetric analysis. The antibacterial activity was tests the result showed that the antibacterial activities of the complexes were significantly improved comparing with ligands.

Abstract: In order to improve the free surface machining accuracy and processing efficiency, this paper proposes a processing parameters such as free surface method, through to the free surface parts for the parameters such as the curvature analysis, and then get free surface modeling geometry characteristic change rule, choose reasonable parameters optimization cutting knife, a path, the improvement of the machining accuracy and processing efficiency. We introduce the conception of curvature to analyze the curvature and optimize the cutting parameter and cutting tool parameter to avoid interference phenomena happening and improve the processing efficiency and precision. Take the ball end cutter for example to process simulation, it shows that through the analysis of the free surface curvature method to avoid the intervention process is feasible, and has been verified by the experiment.

Abstract: The influence of pH of emulsified asphalt, the kinds and content of emulsifiers and stabilizers on asphalt-aggregate adhesion have been investigated in this paper. Results show that the pH of the emulsified asphalt has great impact on asphalt-aggregate adhesion by way of the effect of pH on asphalt, asphalt-aggregate adhesion is worst when asphalt emulsion at pH≈4, which is close to the isoelectric point of asphalt, the bigger the zeta potential absolute value of emulsified asphalt, the better the asphalt-aggregate adhesion property. Effect of emulsifiers on asphalt-aggregate adhesion is complex, the best dosage is at 0.2%. The addition of organic stabilizers are superior to inorganic stabilizers to improve the asphalt-aggregate adhesion, the best dosage is at 0.4%. Effect of mixing emulsifier and stabilizer is better than single-doped emulsifier and stabilizer.

Abstract: In order to reduce the road asphalt fumes in the process of construction, the paper proposed to add some substances in asphalt to reduce the yield of asphalt fumes. Firstly, considering the theory of how the asphalt fumes come into being in the process of construction on the pavement, six possible additives to restrain these fumes havd been screened out. And tests of fumes suppression effect had been done to get the results that: SBS has a good effect of fumes suppression. When added by 3%, the asphalt fumes reduced by the rate of 19.2%; PE has an suppressive effect on asphalt fumes. When added by 3%, the asphalt fumes reduced by the rate of 6.5%; Melamine has a good effect of fumes suppression. When added by 3%, the asphalt fumes reduced by the rate of 45.1%; Ammonium molybdophosphate has an abnormal effect of fumes suppression. When added by 1%, the asphalt fumes not only did not reduce but increases. When added by 3%, the asphalt fumes reduced by the rate of 23.3%; nanoCalcium carbonate has an effect of fumes suppression. When added by 3%, the asphalt fumes reduced by the rate of 4.8%; Activated Carbon has a good effect of fumes suppression. When added by 3%, the asphalt fumes reduced by the rate of 41.6%.

Abstract: Lithium secondary batteries have been widely used in the portable electric devices as power source. Recently it is expected that the realm of its applications expands to the markets such as energy storage medium of hybrid electric vehicle (HEV), electric vehicle (EV). Cathode active material is crucial in terms of performance, durability, capacity of lithium secondary batteries. It is urgent to develope the technology for mass production of cathode material to cope with the markets' demands in the near future. In this study, a calcination furnace running in real production line is modelled in 3D, and the thermal flow and gas flow after chemical reaction in the furnace is analyzed through numerical computations. Based on the results, it is shown that large volume of CO2 gas is generated from chemical reaction. High concentration of CO2 gas and it's stagnation is clearly found from the reactant containers in which the reaction occur to the bottom area of the furnace. It is also studied that 15% or more CO2 mol fraction could affect to proper formation of LiCoO2 through TGA-DSC analysis. The solutions to evacuate carbon dioxide from the furnace are suggested through the change of furnace design and operating condition as well. Keywords : Secondary battery, cathode material, calcination furnace, LiCoO2