Free-volume dependent pressure sensitivity of Zr-based bulk metallic glass

Dubach, Alban and Prasad, K Eswar and Raghavan, Rejin and Loeffler, Joerg F (2009) Free-volume dependent pressure sensitivity of Zr-based bulk metallic glass. In: Journal of Materials Research, 24 (8). pp. 2697-2704.

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Abstract

Instrumented indentation experiments on a Zr-based bulk metallic glass (BMG) in as-cast, shot-peened and structurally relaxed conditions were conducted to examine the dependence of plastic deformation on its structural state. Results show significant differences in hardness, H, with structural relaxation increasing it and shot peening markedly reducing it, and slightly changed morphology of shear bands around the indents. This is in contrast to uniaxial compressive yield strength, sigma(y), which remains invariant with the change in the structural state of the alloys investigated. The plastic constraint factor, C = H/sigma(y), of the relaxed BMG increases compared with that of the as-cast glass, indicating enhanced pressure sensitivity upon annealing. In contrast, C of the shot-peened layer was found to be similar to that observed in crystalline metals, indicating that severe plastic deformation could eliminate pressure sensitivity. Microscopic origins for this result, in terms of shear transformation zones and free volume, are discussed.

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:	08 Mar 2010 11:00
Last Modified:	19 Sep 2010 05:56
URI:	http://eprints.iisc.ac.in/id/eprint/26024

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