Authors: Hyeon Taek Son, J.M. Hong, Ik Hyun Oh, Jae Seol Lee, T.S. Kim, Kouichi Maruyama
Abstract: Mg97Zn1Y2 alloy powders were prepared from gas atomization process, followed by
consolidation using spark plasma sintering (SPS) process. The atomized Mg97Zn1Y2 alloy particles
were entirely spherical in shape and dendrite microstructure. The compacts sintered by SPS process
have values more than 99% of theoretical density. The compressive yield strength was decreased as
sintering temperature increased. It is found that the compressive strength showed the maximum value
of 303MPa at the sintered specimen under load of 250MPa at 350°C.
1517
Authors: Thangaraju Shanmugasundaram, Martin Heilmaier, V. Subramanya Sarma, B.S Murty
Abstract: Bulk nanostructured Al-4Cu alloy was synthesized by high energy ball milling followed by vacuum hot pressing. Its thermal stability was investigated up to 450°C using differential scanning calorimetry, X-ray diffraction, and transmission electron microscopy. The results showed that grain growth in this Al-4Cu alloy was very limited and grain sizes in the range of 100 nm were still present in the alloys after exposure to 450 °C corresponding to a temperature as high as 0.77 T/Tm. The TEM investigations reveal that such a high thermal stability against grain growth observed in this alloy is attributed to the presence of ultrafine dispersoids.
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Authors: Chang Jiang Song, Yuan Yi Guo, Liang Zhu, Ke Feng Li, Min Yang, Qi Jie Zhai
Abstract: High chromium cast iron alloys are widely used to produce wear resistant components. However, formation of the large carbides restricts their applied range for the components by traditional solidification techniques. The gas atomization is an effective approach to refine their structures, improve their properties and extend their application field. Based on the study of structure evolution of atomized powders of Fe-25Cr-3.9C alloy, this paper investigated the structure evolution of the atomized powders of Fe-25Cr-3.9C alloy with addition of Ni and B elements. It is found that addition of Ni and B elements make more primary lath-shaped phase be formed. As particle size decrease, width of the primary lath-shaped phase gradually decreases, and the structures are all composed of lath-shaped phase in the small powders with diameter less than 38mm. At last, a relative study between two alloys was made, and the structure formation of atomized powders was discussed.
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Authors: Li Zhen Wang, Yan Juan Han, Kai Qing Zhang, Kun Wang
Abstract: The electrochemical behaviors of zinc electrode containing Bi, In and Al were tested to study aluminum acting on the electrochemical performance of zinc anode using anodic polarization and tafel profiles measurement. The element distributions of IBA alloy were observed by scanning electron microscope (SEM). Our recent investigations demonstrate that the electrochemical activity of zinc alloy could be improved largely through integrating the optimization content of aluminum into zinc alloy. The SEM images show that there are obvious differences in the element distributions of surface, subsurface or bulk phase, especially, the segregation of Al in subsurface or bulk. The electrochemical behaviors of IBA alloy are related to its physical properties.
590
Authors: György Thalmaier, Ioan Vida-Simiti, N. Jumate, Viorel Aurel Şerban, C. Codrean, Mircea Nicoară, L. Bukkosi
Abstract: Nickel–titanium- group 5A metal (V, Nb, Ta, Zr) alloys are known as promising hydrogen-selective membrane materials. They can potentially be used in membrane reactors, which can produce high-purity H2 and CO2 streams from coal-derived syngas at elevated temperatures. The master alloys were prepared by arc melting using high purity metals in a Ti-gettered argon atmosphere. The alloys were melted several times in order to improve homogeneity. The ingots were induction-melted under a high-purity argon atmosphere in a quartz tube and graphite crucible injected through a nozzle onto a Cu wheel to produce rapidly solidified amorphous ribbons. Thermal stability of the Ni40Ti40Nb20 and Ni32Ti48Nb20 thin tapes has been examined using DTA analysis.
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