Near-threshold fatigue crack growth in bulk metallic glass composites

Boopathy, Kombaiah and Hofmann, Douglas C and Johnson, William L and Ramamurty, Upadrasta (2009) Near-threshold fatigue crack growth in bulk metallic glass composites. In: Journal of Materials Research, 24 (12). pp. 3611-3619.

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Abstract

A major drawback in using bulk metallic glasses (BMGs) as structural materials is their extremely poor fatigue performance. One way to alleviate this problem is through the composite route, in which second phases are introduced into the glass to arrest crack growth. In this paper, the fatigue crack growth behavior of in situ reinforced BMGs with crystalline dendrites, which are tailored to impart significant ductility and toughness to the BMG, was investigated. Three composites, all with equal volume fraction of dendrite phases, were examined to assess the influence of chemical composition on the near-threshold fatigue crack growth characteristics. While the ductility is enhanced at the cost of yield strength vis-a-vis that of the fully amorphous BMG, the threshold stress intensity factor range for fatigue crack initiation in composites was found to be enhanced by more than 100%. Crack blunting and trapping by the dendritic phases and constraining of the shear bands within the interdendritic regions are the micromechanisms responsible for this enhanced fatigue crack growth resistance.

Item Type:	Journal Article
Publication:	Journal of Materials Research
Publisher:	The Materials Research Society
Additional Information:	Copyright of this article belongs to The Materials Research Society.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	10 Mar 2010 06:21
Last Modified:	19 Sep 2010 05:56
URI:	http://eprints.iisc.ac.in/id/eprint/26068

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