Papers by Keyword: Gas Atomization

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Authors: Xin An Dang, Li Li Wang, Li Jun Yang
Abstract: On the basis of technologies of gas atomization, supersonic gas atomization, surface effect of electric charge and jet, we design a new-style device of two fluids atomization with the combination of solid atomization and electric field utilizing a LAVAL nozzle, a delivery tube of sectional type and the electrical field dispersion technique. The soldering tin of 63 A was atomized with the air, and the powder prepared was analyzed by optical granularity analyzer, nanometer magnetic particles and Zeta potential analyzer. The results show that the particle size with less than 8μm can reach 75%; the average particle size is 1.7612μm, and the first peak in the distribution curve is about 500 nm, which is an order of magnitude smaller than that the existing reported peak. The compound atomization device can refine the particle size of powers effectively, improve uniformity, yielding rate, and the purity of atomized powders and has a significant effect on atomizing, thus provides powerful supports for preparing ultra fine metal powders with high efficiency and low energy consumption and has a good prospect in application.
741
Authors: K.R. Cardoso, Asuncion Garcia Escorial, M. Lieblich, Alain Reza Yavari, Walter José Botta Filho
253
Authors: Tze Yang Yeh, Kuo Yuan Peng
Abstract: Metallic composite materials are mainly manufactured by powder metallurgy (PM) or casting, with reinforced ceramic particulates dispersed in a metal matrix. The current study presents an investigation with respect to simultaneously gas-atomized spherical Ti/TiC composite powders. Various analytical methods are used to characterize the gas-atomized Ti/TiC composite powders, including XRD, laser particle size analysis, flow rate tests, apparent density and tap density tests, SEM, and alike. The spherical Ti/TiC composite powders will be further laser sintered at the next stage to utilize mechanical properties testing.
302
Authors: Muh Ron Wang, Pin Jen Chen, Je Rei Yang, Jin Shen Chiu, Tien Chu Lin, Teng Sun Lai
Abstract: This paper describes the performance of an atomizer coupled with a substrate which produces metal powder and spray forming materials simultaneous in the spray chamber. Ultra fine metal powders are produced from this process. The melt is atomized by a twin-fluid atomizer with internal mixing mechanisms. The molten spray injected from the swirling chamber of the atomizer is then impinged upon the substrate to form the two phase impinging flow. The deposition rate of the molten spray on the substrate is controlled by the diameter of the substrate, the height of the substrate ring and the distance of the substrate from the outlet of the atomizer. This in turn determines the powder production rate of the spraying processes. Experimental results indicate that the deposition rate of the spray forming material decreases as the distance between the substrate and the atomizer increases. For example, the deposition rate decreases from 48% to 19% as the substrate is placed at a distance from 20cm to 40cm. On the other hand, the metal powder production rate and its particle size increases as the substrate is placed far away from the atomizer. The production of metal powder with mean particle size as low as 3μ m level has been achieved, a level which is not achievable by the conventional gas atomization processes.
1237
Authors: Yong Jin Kim, Jin Chun Kim, Jung Ho Ahn
Abstract: Hypereutectic prealloyed Al-20wt.%Si powders were prepared by the gas atomization process. Characteristics of the atomized Al-Si powders were investigated. With increasing gas pressure of the atomization, the average powder size and oxygen content decreased. Primary Si particles in the as-atomized powders were about 8-10 ㎛. Sintering behavior of the atomized Al-Si powders was discussed with sintering temperature. As-atomized powders were hot-pressed and extruded into a cylindrical shape. 96-99% of theoretical density was achieved by the hot consolidation. Microstructure changes as well as hardness and tensile properties of the samples were evaluated in this paper.
2633
Authors: Guo Qiang Xie, Dmitri V. Louzguine-Luzgin, Mikio Fukuhara, Hisamichi Kimura, Akihisa Inoue
Abstract: We investigated consolidation behavior of gas-atomized Cu50Zr45Al5 metallic glassy alloy powders by a spark plasma sintering (SPS) process. Density of the sintered samples increased with an increase in sintering temperature. The nearly full density samples without crystallization could be attained by the SPS process at sintering temperature of 693 K under pressure of 600 MPa. The produced samples exhibited high-strength and met large-size requirement. The SPS process makes it possible to fabricate the large-size bulk metallic glasses without limitation of dimensions and alloy system.
1086
Authors: Yoshihito Kawamura, Akihisa Inoue
709
Authors: Chun Jiang Kuang, H. Zhong, D. Chen, X. Kuang, Q. Li, Q. Hao
Abstract: Nitrogen alloying in steel may greatly increase the strength and corrosion resistance of the material. This paper introduced some research results of high nitrogen stainless steel (HNS) investigation via PM process. Nickel free high nitrogen stainless steels (17Cr12Mn2MoN) and superaustenitic high nitrogen stainless steels (28Cr6Mn2/6Mo10/20NiN) were investigated via gas atomization and HIP processes. Nitrogen alloying behavior during atomization and consolidation processes was investigated. Powders with nitrogen content up to 1% were manufactured by gas atomization process. Nickel free high nitrogen stainless steels with nitrogen up to 0.6% exhibits high strength and ductility at as-HIPed and solution annealed state, and superaustenitic HNS with nitrogen content up to 1% showed very high strength and good ductility at solution annealed state, with b at 1100 MPa, s at 810 MPa and elongation of 43%. PM HNS exhibited excellent corrosion resistance.
1811
Authors: Jie Wu, Lei Xu, Zheng Guan Lu, Rui Peng Guo, Yu You Cui, Rui Yang
Abstract: Pre-alloyed powder of Ti-47Al-2Cr-2Nb-0.15B was prepared by a gas atomization process and powder metallurgy (PM) γ-TiAl alloys were made through a hot isostatic pressed (HIPed) route. The atomized powders were canned in containers, degassed, sealed, and HIPed. Effect of two different canning materials (mild steel and commercial pure titanium (CP-Ti)) on the microstructure and properties of as-HIPed γ-TiAl alloy were discussed. Due to the reaction between mild steel containers and γ-TiAl at relative high temperature (over 1230 °C), the γ-TiAl matrix is contaminated. CP-Ti canned γ-TiAl showed bigger yield and fracture strength than mild steel canned TiAl. PM γ-TiAl alloy parts having complex shape could be manufactured by the near net-shape process.
604
Authors: S.Y. Chang, Du Hyung Lee, H.G. Cho, Yo Seung Song, Sung Ho Kim, Chan Bock Lee
Abstract: The Mg-6wt%Al-1wt%Zn alloy powders mixture produced by gas atomization were spark plasma sintered (SPSed). The SPSed sample was coated by plasma electrolytic oxidation (PEO) method, and the microstructure, mechanical and corrosion properties were investigated and compared to the normally sintered sample. The SPSed sample exhibited a microstructure of well-bonded grains with approximately 48 ,m in grain size, which was bigger than that of the normally sintered sample. The coatings on the SPSed sample were characterized by dense and porous layers, while, in the case of the normally sintered sample, the coatings had grown through the grain boundary of substrate with increasing the coating time. The surface roughness, thickness and micro-hardness of coatings on the SPSed sample increased gradually with increasing the coating time. The corrosion property of coatings on the SPSed sample had a tendency to improve with increasing the coating time in 3.5%NaCl solution. However, it was worse than that of coatings on the normally sintered sample.
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