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On the microstructure–tensile property correlations in bulk metallic glass matrix composites with crystalline dendrites

Narayan, R. L. and Singh, P. S. and Hofmann, D. C. and Hutchinson, N. and Flores, K. M. and Ramamurty, U. (2012) On the microstructure–tensile property correlations in bulk metallic glass matrix composites with crystalline dendrites. Acta Materialia, 60 (13-14). pp. 5089-5100. ISSN 1359-6454. https://resolver.caltech.edu/CaltechAUTHORS:20121008-071648981

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Abstract

Bulk metallic glass (BMG) matrix composites with crystalline dendrites as reinforcements exhibit a wide variance in their microstructures (and thus mechanical properties), which in turn can be attributed to the processing route employed, which affects the size and distribution of the dendrites. A critical investigation on the microstructure and tensile properties of Zr/Ti-based BMG composites of the same composition, but produced by different routes, was conducted so as to identify “structure–property” connections in these materials. This was accomplished by employing four different processing methods—arc melting, suction casting, semi-solid forging and induction melting on a water-cooled copper boat—on composites with two different dendrite volume fractions, V_d. The change in processing parameters only affects microstructural length scales such as the interdendritic spacing, λ, and dendrite size, δ, whereas compositions of the matrix and dendrite are unaffected. Broadly, the composite’s properties are insensitive to the microstructural length scales when V_d is high (∼75%), whereas they become process dependent for relatively lower V_d (∼55%). Larger δ in arc-melted and forged specimens result in higher ductility (7–9%) and lower hardening rates, whereas smaller dendrites increase the hardening rate. A bimodal distribution of dendrites offers excellent ductility at a marginal cost of yield strength. Finer λ result in marked improvements in both ductility and yield strength, due to the confinement of shear band nucleation sites in smaller volumes of the glassy phase. Forging in the semi-solid state imparts such a microstructure.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.actamat.2012.06.032DOIUNSPECIFIED
http://www.sciencedirect.com/science/article/pii/S1359645412004041PublisherUNSPECIFIED
Additional Information:© 2012 Acta Materialia Inc. Published by Elsevier Ltd. Received 10 April 2012; received in revised form 14 June 2012; accepted 16 June 2012. Available online 22 July 2012. The authors thank Liquidmetal Technologies Inc., Rancho Margarita, CA for donating materials for this research. Research work on BMGs at IISc was supported through a Swarna Jayanthi Fellowship (U.R.). A portion of this work (D.H., N.H., K.M.F.) was supported by the Air Force Office of Scientific Research under Grant No. FA9550-09-1-0251.
Funders:
Funding AgencyGrant Number
Liquidmetal Technologies Inc., Rancho Margarita, CAUNSPECIFIED
Swarna Jayanthi FellowshipUNSPECIFIED
Air Force Office of Scientific Research (AFOSR)FA9550-09-1-0251
Subject Keywords:Metallic glass; Composites; Microstructure; Plastic deformation; Shear bands
Issue or Number:13-14
Record Number:CaltechAUTHORS:20121008-071648981
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20121008-071648981
Official Citation:R.L. Narayan, P.S. Singh, D.C. Hofmann, N. Hutchinson, K.M. Flores, U. Ramamurty, On the microstructure–tensile property correlations in bulk metallic glass matrix composites with crystalline dendrites, Acta Materialia, Volume 60, Issues 13–14, August 2012, Pages 5089-5100, ISSN 1359-6454, 10.1016/j.actamat.2012.06.032. (http://www.sciencedirect.com/science/article/pii/S1359645412004041)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34730
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:08 Oct 2012 15:02
Last Modified:03 Oct 2019 04:21

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