Effect of Gallium on microstructure and mechanical properties of Nb-Si eutectic alloy

Kashyap, S and Tiwary, CS and Chattopadhyay, K (2011) Effect of Gallium on microstructure and mechanical properties of Nb-Si eutectic alloy. In: Intermetallics, 19 (12). pp. 1943-1952.

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Abstract

In this paper, we report a significant improvement in mechanical properties of near eutectic Nb-Si alloys by addition of Gallium (Ga) and control of microstructural length scale. A comparative study of two alloys Nb-18.79 at.%Si and Nb-20.2 at.%Si-2.7 at.%Ga were carried out. The microstructure refinements were carried out by vacuum suction casting in water cooled thick copper mold. It is shown that addition of Ga suppresses Nb(3)Si phase and promotes beta-Nb(5)Si(3) phase. The microstructural length scale and in particular eutectic spacing reduces significantly to 50-100 nm in suction cast ternary alloys. Compression test shows a strength of 2.8 +/- 0.1 GPa and plasticity of 4.3 +/- 0.03%. In comparison, the binary Nb-18.79 at.%Si alloy processed under identical conditions exhibit coarser length scale (300-400 nm) and brittle behavior. The fracture toughness of Ga containing suction cast alloy shows a value of 24.11 +/- 0.5 MPa root m representing a major improvement for bulk Nb-Si eutectic alloy. (C) 2011 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	Intermetallics
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Intermetallics;miscellaneous;Phase transformation; Brittleness and ductility;Alloy design;Microscopy;various
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	01 Dec 2011 10:32
Last Modified:	01 Dec 2011 10:32
URI:	http://eprints.iisc.ac.in/id/eprint/42399

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