Papers by Keyword: X-Ray Diffractometry

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Authors: Tsunenobu Kimoto, Toshihiro Yamamoto, Zhi Yong Chen, Hiroshi Yano, Hiroyuki Matsunami
Authors: J.S. Kim, I.T.H. Chang, C. Lucien Falticeanu, G.J. Davies, Kyle Jiang
Abstract: A new approach is explored to achieve sintered aluminium alloy from metallic powder mixtures without compression or adding Mg. In this approach, mixtures of micron-sized aluminium powder (average size of 2.5 μm) and nano-sized alloying elemental powder of Cu and Sn (less than of 70nm), at appropriate proportions to compositions of Al-6wt%Cu, Al-6wt%Cu-3wt%Sn with and without adhesive binder were prepared by magnetic stirring. Then, the powder mixture was poured into a crucible and heat treated at a temperature of 600°C for 11 hours in inert atmosphere of N2 or Ar. In this paper, we investigate the debinding behavior of loosely packed Al-based powder mixture and the microstructural development and mechanical property sintered parts using a combination of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffractrometry (XRD) and hardness test.
Authors: Rodrigo Estevam Coelho, Ana Cris R. Veloso, Rodinei Medeiros Gomes, Tadeu Antonio de Azevedo Melo, Severino Jackson Guedes de Lima
Abstract: In the present work is shown the results for solid interaction of a Cu-13.4Al-2Ni (wt%) elemental powders. Together with this mixture was placed tungsten carbide balls into a cylindrical vial under argon atmosphere. The weight ratio of the balls to powder was 20 to 1. A planetary ball mill (Fritsch Pulverizette 5) was used to perform MA at 250 rpm. The elemental powder was milled at 10min, 5 and 10 hours and a small amount of the powders were collected and analyzed via X-ray diffraction, using Cu Kα radiation (λ=0.15418 nm) and differential thermal analyses from 25 up to 450oC at a heating rate of 25oC min-1. The x-ray diffraction patterns showed that after 10h of milling the phase formation of the mechanical alloyed powders is composed of a Cu, full Cu(Al) solid solution and γAl9Cu4.
Authors: Dock Young Lee, Jun Hyun Han, Suk Won Kang, Jung-Hwa Mun, Ki Bae Kim
Abstract: In this study, the orientation distribution function (ODF), which can be calculated from the pole figure data, was examined and tried in order to characterize the bulky morphology of primary solid phase of semi-solid slurry instead of erroneous 2D observation for the characterization of microstructure. Al-15wt%Cu alloys were electromagnetically stirred during the continuous cooling in the specially designed electromagnetic (EM) stirrer, which generates a rotating magnetic field, and the samples were prepared by interrupt-quenching semi-solid slurry at a solid-liquid region. Owing to EM stirring the temperature distribution of melt inside a crucible became uniformed compared with the case of unstirred melt and the normal dendritic structure was transformed to one consisting of the spherical and rosette shaped primary solid phase due to the fragmentation of the dendrites. Also by the effect of EM stirring the <110>//ND texture were still strongly developed, but the advancement of the orientations to lead <110>//ND texture became weaker, and the orientations to lead <100>//ND and <111>//ND texture were more strongly advanced in comparison with the unstirred case. Therefore the advancement of the texture became weak and so the tendency to random orientation was appeared due to the EM stirring. Therefore it was thought that the extent of random orientation could be valued for the characterization of bulky morphology of primary solid phase of semi-solid slurry.
Authors: T.M. Tkacheva, G.N. Petrov, Leonid I. Datsenko
Authors: P. Limnonthakul, C. Chananonnawathorn, K. Aiempanakit, J. Kaewkhao, P. Eiamchai, M. Horprathum
Abstract: The ZnO nanorods were fabricated on top of the seeded gold layer by the aqueous solution method with the solution of zinc nitrate and hexamethylenetetramine (HTMA) at 90°C for 24 hours. The variety of the ZnO nanorods were prepared and investigated based on the precursor concentrations, in a range of 1 to 40 mM. The physical morphologies and crystal structures were characterized by field-emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD), respectively. The results showed that, with the small precursor concentrations, the lateral growth of the nanorods was highly significant when compared to their axial growth. The precursor concentration of 20 mM was best optimized for the preparation of the ZnO nanorod arrays with the hexagonal structures at the highest rod diameter and length. At the higher concentrations, although the nanorod size remained nearly constant, the length was however rapidly decreased. Further analyses also proved that, with the increased precursor concentrations, the number density of the ZnO nanorods was progressively increased along with the more complete hexagonal wurtzite structures.
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