Effect of Mg addition on microstructural, mechanical and environmental properties of Nb-Si eutectic composite

Tiwary, CS and Kashyap, S and Chattopadhyay, K (2013) Effect of Mg addition on microstructural, mechanical and environmental properties of Nb-Si eutectic composite. In: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 560 . pp. 200-207.

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Abstract

The paper reports the effect of addition of small amount of Mg on the mechanical and oxidation properties of Nb-Nb3Si eutectic composites in Nb-Si system under the condition of suction casting. Mg addition increases the volume fraction of primary dendrites of Nb solid solution. This phase contains significant amount of strengthening precipitates. Two different precipitates are identified. The large plate shaped precipitates are that of hcp phase, while fine coherent precipitates have the structure similar to recently identified delta-Nb11Si2 phase. The Mg addition improves both the strength and ductility of the composite at room temperature (similar to 1.4 GPa and similar to 5% engineering strain) as well as at 700 degrees C(similar to 1.2 GPa and similar to 7% engineering strain). The presence of Mg results in a complex barrier layer which significantly increases the oxidation resistance up to a temperature of at least 1000 degrees C. (C) 2012 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Publisher:	ELSEVIER SCIENCE SA
Additional Information:	Copyright for this article belongs to ELSEVIER SCIENCE SA, SWITZERLAND
Keywords:	Electron microscopy;Hardness measurement;X-ray diffraction;Mechanical characterization;Intermetallics;Casting
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	18 Feb 2013 08:53
Last Modified:	18 Feb 2013 08:53
URI:	http://eprints.iisc.ac.in/id/eprint/45766

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