Metallurgy Technology and Materials

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Authors: Ji Man Luo, Yang Jiang, Zhi Hui Xing
Abstract: In order to avoid the damage of structure caused by the vibration, the natural frequency and vibration mode figure of the stiffness characteristics of the hoist’s structure should be analyzed. Modal analysis method is presented for solving above problem, and the first 6 order natural frequencies in different working conditions have been calculated in this paper. Vibration mode figure of structure system have been simulated corresponding to the first 6 order natural frequencies based on ANSYS. It is shows that the external excitation force have a great influence on the top of the free end when the cage moves to a different location. So, in the actual construction, the stiffness of top free ends connected tie-in device should be strengthened, therefore the system stability will be improved.
Authors: Jian Huang, Yi Min, Cheng Jun Liu, Mao Fa Jiang
Abstract: To improve the quality controlling of pipeline steel and to avoid mis-down grade, the cleaness including content of non-metallic inclusions, total oxygen and nitrogen of the first continuous casting slags of X70 pipeline steel were investigated. Results showed that, content of total oxygen, nitrogen, large non-metallic inclusions and inclusions areal density decrease with casting length increasing gradually. But at casting length of about 5.0 m which is just during the drastic changeing period of casting speed approaching to stead casting state, the content of large non-metallic inclusions and inclusions areal density increases abruptly induced by the entrapment of mold powders. Thus, to decrease the degradation rate of pipeline slab, the increasing rate of casting speed should be adjusted more evenly.
Authors: Ling Cheng, De Gui Zhu, Ying Gao, Wei Li, Bo Wang
Abstract: Alumina reinforced aluminum matrix composites (Al-5wt.%Si-Al2O3) fabricated by powder metallurgy through hot isotactic pressing were sintered in different processes, i.e. solid and liquid phase sintering. Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-ray (EDX) techniques were used to characterize the sintered composites. The effects of solid phase and liquid phase sintering on density, microstructure, microhardness, compression and shear strength were investigated. It was found that in situ chemical reaction was completed in solid phase sintering, but the composites had lower microhardness, comprehension and shear strength due to low density and segregation of alumina and Si particles in microstructure. Segregation of reinforcement particles in solid phase sintering resulted from character of solid reaction and Si diffusion at high temperature over a long hold time.
Authors: Zhong Hui Ye, Qing Lin, Hai Fu Huang, Yun He, Shao Hong Chen
Abstract: The cyano-bridged complexe [Gu(en)x]yMA[Fe(CN)6]z·nH2O(MA=K+) have been synthesized. In the compound [Cu(en)2][KFe(CN)6]·H2O, we shows firstly a weak intramolecular anti-ferromagnetic coupling between Fe3+(ground state 5T2g, S=1/2) and Cu2+(ground state 6T2g3eg, S=1/2) through the long- range cyano bridges. The magnetic susceptibility obey the curie-weiss law [χ=C/(T-θ)] with a negative weiss constant,the curie constant C=0.42cm3·k·mol-1, the compound exists a strong Cu2+–CN–Fe3+ ferromagnetic interaction and a weak Cu2+(ground state 6T2g3eg, S=1/2)–Cu2+(ground state 6T2g3eg, S=1/2) antiferromagnetic interaction, through long range of NC-Fe-CN. At the same time, we have given an explanation from magnetic properties and struction of compounds.
Authors: Hua Qing Wang, Rui Li, Cheng Xuan Xiang
Abstract: Nanosized ZnO was prepared successfully by solid phase coordination chemistry reaction and characterized by XRD and TEM techniques. The results of CV testing indicated that the peak shapes in CV diagrams were differed for the three electrodes when the scan rate was 1 mV s-1. The mixture electrode (sample D) that nanosized ZnO additives were 50% exhibited remarkable cyclic reversibility. The results indicated that the optimum ratio of ZnO additives were 50% by means of constant current charge-discharge. The rechargeability of the Zn electrode could be improved. But the nanosized ZnO were more effective in modifying Zn electrode than the common ZnO particles. Its discharge capacity at 25th and 30th charge-discharge cycle achieves 220 mAh g-1 and 198 mAh g-1, respectively.
Authors: Cheng Lin Li, Dong Geun Lee, Wen Jun Ye, Xu Jun Mi, Yong Tae Lee
Abstract: The microstructure evolution of a new designed metastable beta Ti-9.2Mo-2Fe alloy during aging treatment was investigated by TEM. The results revealed that athermal ω phases were observed in SAD pattern during water quenching from above the β transus temperature for the alloy. As well, isothermal ω phases were found during aging at 500 °C even though they have a limited time of stability. The coexistence of ω and α phase was found in the early aging time and the pre-formed ω phase during aging undergoes coarsening and act as uniformly distributed nucleation sites for α precipitation during subsequent isothermal aging treatment. A consequence of such ω- assisted nucleation is that relatively large amount of α precipitations are formed and fine distributed in β matrix. In addition, the α precipitations are of a relatively finer size scale (nanometers to sub micrometers).
Authors: Hai Bo Wang, Xi Bao Wang, Hui Li
Abstract: In this paper, metal reduction preparation of TiB2 powder via magnesium reduction and aluminothermic reduction were studied. The carbon rod arc heating generated from the spread of the reaction of TiB2,and then the examinations were performed after pickling, crushing and grinding such as SEM and XRD. The results showed that the aluminothermic reduction occurred into the powder impurity phase less, but the need for better technology separation of Al2O3. Magnesium reduction reaction products with more impurities, pickling process removes only the reactants of MgO and other impurities not removed in the air and impurities were analyzed and compared.
Authors: Jung Hwa Seo, Dong Geun Lee, Cheng Lin Li, Xu Jun Mi, Yong Tae Lee
Abstract: Microstructure characterization and hardening behavior of a new designed Ti-12.1Mo-1Fe alloy during solution and aging treatment was investigated in the present study by OM, Vickers hardness. The results showed that the beta transus temperature of new Ti-12.1Mo-1Fe alloy was about 780°C. Further observation of ω phase should be performed by TEM later. It is also found that ω phase played a more important role than α phase in hardening. The hardening due to ω phase can lead to a high hardness about 470 Hv but the coarse α phases result in a hardness below 300 Hv.
Authors: Z.L. Li, J.Y. Zhou, Z.P. Wang, J.H. Gu, Y.W. Zhang, Y.X. Wei
Abstract: Indium oxide flowerlike films were prepared on glass substrate by a simple chemical vapor deposition (CVD) coating technique. The results showed the products on the glass surface are flowerlike body centered cubic structure of In2O3 films. The flowerlike microstructures are distributed uniformly and have less overlapping, the diameters of them are about 3 µm. The deposition mechanism and the morphologies control procedure of the In2O3 were studied. As the reaction time increases, the morphologies of the microstructures were changed from cocoon-like particles to hybrid thin films, and flowerlike microstructures at last. This novel CVD method might provide a simple route for synthesizing other metal oxide or compound films.

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