The Experts below are selected from a list of 25332 Experts worldwide ranked by ideXlab platform
Fuquan Zhao - One of the best experts on this subject based on the ideXlab platform.
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fabrication of b4c particulate reinforced Magnesium matrix composite by powder Metallurgy
Journal of Alloys and Compounds, 2005Co-Authors: Q Jiang, Huiyuan Wang, B X, Y Wang, Fuquan ZhaoAbstract:Abstract Magnesium Metal matrix composites (MMCs) reinforced with various fractions of 10, 15 and 20 vol.% B 4 C particulates fabricated by powder Metallurgy (P/M) technique were investigated. Microstructure characterization of the composites revealed necklace distribution of B 4 C particulates in the matrix material and the presence of minimal micro-porosity. The X-ray diffraction (XRD) showed the formation of MgO and MgB 2 in B 4 C/Mg composites. Moreover, the results revealed that the hardness and wear resistance of the composites were higher than those of as-cast Mg ingot and increased with increasing amount of B 4 C particulates from 10 to 20 vol.%.
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fabrication of tib2 particulate reinforced Magnesium matrix composites by powder Metallurgy
Materials Letters, 2004Co-Authors: Huiyuan Wang, Q Jiang, B X, Y Wang, Fuquan ZhaoAbstract:Magnesium Metal matrix composites (MMCs) reinforced with 10, 20 and 30 vol.% TiB2 particulates, respectively, were fabricated by powder Metallurgy. The microstructure, porosity, hardness and abrasive wear behavior of the composites were evaluated. Microstructural characterization of Mg MMCs showed generally uniform reinforcement distribution. As compared with pure Mg, the hardness (HB) values of Mg MMCs reinforced with 10, 20 and 30 vol.% TiB2 particulates were increased by 41%, 106% and 181%, respectively. The abrasive wear tests showed that the wear resistance of Mg MMCs is increased with the increasing of the reinforcement volume fraction. This was due to the strong particulate-matrix bonding and high hardness of the TiB2 particulate.
S K Panigrahi - One of the best experts on this subject based on the ideXlab platform.
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synthesis characterization and mechanical properties of in situ tic tib2 reinforced Magnesium matrix composite
Materials & Design, 2016Co-Authors: B N Sahoo, S K PanigrahiAbstract:Abstract Cast Magnesium-Metal matrix composites are widely used in automotive and aerospace industries due to high strength-to-weight ratio and good damping properties. In the present work, a novel hybrid method has been adopted to fabricate TiC-TiB2 reinforced Magnesium matrix composites. The reinforcement is formed in-situ from elemental Ti and B4C powders and molten Mg-Al-Zn alloy without any addition of a third phase Metal powder such as aluminum. Results show that the distribution of TiC and TiB2 reinforcing phases in the Magnesium matrix is more uniform when the composite is fabricated at 900 °C for 2 h. The base and composite materials were subjected to homogenization treatment which resulted in dissolution of β-Mg17Al12 phase into α-Mg matrix and enhances the strength and ductility by 22% and 50% in base and 17% and 50% in composite respectively. The enhancement of mechanical properties in the homogenized in-situ composites is explained in detail by analyzing the fractographs and microstructures of the material.
Q Jiang - One of the best experts on this subject based on the ideXlab platform.
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fabrication of b4c particulate reinforced Magnesium matrix composite by powder Metallurgy
Journal of Alloys and Compounds, 2005Co-Authors: Q Jiang, Huiyuan Wang, B X, Y Wang, Fuquan ZhaoAbstract:Abstract Magnesium Metal matrix composites (MMCs) reinforced with various fractions of 10, 15 and 20 vol.% B 4 C particulates fabricated by powder Metallurgy (P/M) technique were investigated. Microstructure characterization of the composites revealed necklace distribution of B 4 C particulates in the matrix material and the presence of minimal micro-porosity. The X-ray diffraction (XRD) showed the formation of MgO and MgB 2 in B 4 C/Mg composites. Moreover, the results revealed that the hardness and wear resistance of the composites were higher than those of as-cast Mg ingot and increased with increasing amount of B 4 C particulates from 10 to 20 vol.%.
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fabrication of tib2 particulate reinforced Magnesium matrix composites by powder Metallurgy
Materials Letters, 2004Co-Authors: Huiyuan Wang, Q Jiang, B X, Y Wang, Fuquan ZhaoAbstract:Magnesium Metal matrix composites (MMCs) reinforced with 10, 20 and 30 vol.% TiB2 particulates, respectively, were fabricated by powder Metallurgy. The microstructure, porosity, hardness and abrasive wear behavior of the composites were evaluated. Microstructural characterization of Mg MMCs showed generally uniform reinforcement distribution. As compared with pure Mg, the hardness (HB) values of Mg MMCs reinforced with 10, 20 and 30 vol.% TiB2 particulates were increased by 41%, 106% and 181%, respectively. The abrasive wear tests showed that the wear resistance of Mg MMCs is increased with the increasing of the reinforcement volume fraction. This was due to the strong particulate-matrix bonding and high hardness of the TiB2 particulate.
Huiyuan Wang - One of the best experts on this subject based on the ideXlab platform.
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fabrication of b4c particulate reinforced Magnesium matrix composite by powder Metallurgy
Journal of Alloys and Compounds, 2005Co-Authors: Q Jiang, Huiyuan Wang, B X, Y Wang, Fuquan ZhaoAbstract:Abstract Magnesium Metal matrix composites (MMCs) reinforced with various fractions of 10, 15 and 20 vol.% B 4 C particulates fabricated by powder Metallurgy (P/M) technique were investigated. Microstructure characterization of the composites revealed necklace distribution of B 4 C particulates in the matrix material and the presence of minimal micro-porosity. The X-ray diffraction (XRD) showed the formation of MgO and MgB 2 in B 4 C/Mg composites. Moreover, the results revealed that the hardness and wear resistance of the composites were higher than those of as-cast Mg ingot and increased with increasing amount of B 4 C particulates from 10 to 20 vol.%.
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fabrication of tib2 particulate reinforced Magnesium matrix composites by powder Metallurgy
Materials Letters, 2004Co-Authors: Huiyuan Wang, Q Jiang, B X, Y Wang, Fuquan ZhaoAbstract:Magnesium Metal matrix composites (MMCs) reinforced with 10, 20 and 30 vol.% TiB2 particulates, respectively, were fabricated by powder Metallurgy. The microstructure, porosity, hardness and abrasive wear behavior of the composites were evaluated. Microstructural characterization of Mg MMCs showed generally uniform reinforcement distribution. As compared with pure Mg, the hardness (HB) values of Mg MMCs reinforced with 10, 20 and 30 vol.% TiB2 particulates were increased by 41%, 106% and 181%, respectively. The abrasive wear tests showed that the wear resistance of Mg MMCs is increased with the increasing of the reinforcement volume fraction. This was due to the strong particulate-matrix bonding and high hardness of the TiB2 particulate.
Taner Yildirim - One of the best experts on this subject based on the ideXlab platform.
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nanoconfinement and catalytic dehydrogenation of ammonia borane by Magnesium Metal organic framework 74
Chemistry: A European Journal, 2011Co-Authors: Srinivas Gadipelli, Jamie Ford, Wei Zhou, Terrence J Udovic, Taner YildirimAbstract:Ammonia borane (NH3BH3, AB) has recently received much attention as a promising hydrogen-storage medium among a very large number of candidate materials because of its satisfactory air stability, relatively low molecular mass (30.7 gmol ), and remarkably high energy-storage densities (gravimetric and volumetric hydrogen capacities are 19.6wt% and 140 gL , respectively). However, the direct use of pristine AB as a hydrogen energy carrier in onboard/fuel-cell applications is prevented by its very slow dehydrogenation kinetics below 100 8C and the concurrent release of detrimental volatile by-products such as ammonia, borazine, and diborane. Many different methods have been adopted to promote efficient H2 generation from AB, including catalytic hydrolysis in aqueous solution, ionic liquids, organic solvents, and thermodynamic modifications by formation of hybrid structures with transition Metals, alkali-, or alkaline-earth Metal/hydrides, 12] or nanoconfined phases using porous scaffolds. However, many of these methods rely on the usage of heavy Metal catalysts, aqueous or nonaqueous solutions, and ionic liquids, all of which make the hydrogen density of the systems unacceptably low for practical applications. Furthermore, the vigorous reactions, hygroscopic properties, and water solubility of borohydrides have negative impacts on the dehydrogenation performance and make it difficult to control the release of hydrogen. The other approach is made, in particular, nanocomposition of AB within porous scaffoldings. However, systems still suffers one or more of the followings: either the nanocomposite is heavier or cannot prevent the generation of all the volatile by-products. Hence, more work needs to be done to explore the potential role that catalysts can play to further improve the controllable H2-release kinetics under moderate conditions while at the same time preventing the generation of detrimental byproducts. Over the past few years, porous Metal–organic frameworks (MOFs) have emerged as promising multifaceted materials, combining such functions as catalytic activity, 24] shape-selectivity, templating, and purification. Crystalline MOF structures are composed of Metal sites linked to organic ligands, yielding three-dimensional extended frameworks that often possess considerable porosity. In principle, the combination of nanoporosity and active Metal sites in MOFs makes them potentially useful materials for promoting the decomposition of AB. However, until now, such a use of MOFs has been rare and any future success would depend crucially on the particular choices of a suitable Metal center, pore structure, and thermal stability. For instance, Li et al. were the first to show that Y-based MOF as a solid state decomposition agent for AB. The main drawback of AB-Y-MOF is largely added weight due to the heavy Y Metal. In addition, for the given very narrow pore structure of Y-MOF, as low as approximately 8 wt% of AB loading is achieved for the reported 1:1 mole ratio. Thus, it is highly desirable to have a light weight MOF with stable and suitable nanopore channels that can hold more than one AB molecule. Herein, we show that the porous MgMOF-74 (Mg2ACHTUNGTRENNUNG(DOBDC), DOBDC=2, 5-dioxido-1, 4-benzenedicarboxylate) is a promising candidate for nanoconfinement and catalytic decomposition of AB for clean and efficient H2 generation. Mg-MOF-74 has a rigid framework, composed of one-dimensional (1D) hexagonal channels (Figure 1a) with a nominal diameter of approximately 12 running parallel to the DOBDC ligands. In as-synthesized material, the Mg cations are coordinated with five oxygen atoms from the DOBDC ligands and one oxygen atom from a terminal water molecule. However, upon heating under vacuum, the terminal water molecules can be easily removed, leading to unsaturated (open) Mg Metal sites (decorated on the edges of the hexagonal pore channels) with an open pore structure of high surface area (>1000 mg ). The open Mg Metal sites play a vital role in enhanced binding of various gas molecules (H2, CH4, C2H2, NO, etc. ) and successfully used to promote molecular separation. Figure 1b represents AB confinement within the MOF pores as obtained [a] Dr. S. Gadipelli, Dr. J. Ford, Dr. W. Zhou, Dr. H. Wu, Dr. T. J. Udovic, Dr. T. Yildirim NIST Center for Neutron Research Gaithersburg MD 20899-6102 (USA) Fax: (+1)301-921-9847 E-mail : taner@seas.upenn.edu gsrini@seas.upenn.edu [b] Dr. S. Gadipelli, Dr. J. Ford, Dr. T. Yildirim Department of Materials Science and Engineering University of Pennsylvania, Philadelphia PA, 19104 (USA) [c] Dr. W. Zhou, Dr. H. Wu Department of Materials Science and Engineering University of Maryland, College Park MD, 20742 (USA) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201100090.
