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Published March 31, 2009 | Published
Journal Article Open

Solution to the problem of the poor cyclic fatigue resistance of bulk metallic glasses

Abstract

The recent development of metallic glass-matrix composites represents a particular milestone in engineering materials for structural applications owing to their remarkable combination of strength and toughness. However, metallic glasses are highly susceptible to cyclic fatigue damage, and previous attempts to solve this problem have been largely disappointing. Here, we propose and demonstrate a microstructural design strategy to overcome this limitation by matching the microstructural length scales (of the second phase) to mechanical crack-length scales. Specifically, semisolid processing is used to optimize the volume fraction, morphology, and size of second-phase dendrites to confine any initial deformation (shear banding) to the glassy regions separating dendrite arms having length scales of ≈2 μm, i.e., to less than the critical crack size for failure. Confinement of the damage to such interdendritic regions results in enhancement of fatigue lifetimes and increases the fatigue limit by an order of magnitude, making these "designed" composites as resistant to fatigue damage as high-strength steels and aluminum alloys. These design strategies can be universally applied to any other metallic glass systems.

Additional Information

© 2009 by the National Academy of Sciences. Contributed by William L. Johnson, January 22, 2009 (sent for review December 12, 2008). Published online before print March 16, 2009. M.E.L. and R.O.R. acknowledge financial support from the Director, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, of the U.S. Department of Energy under Contract DE-AC02-05CH11231. D.C.H. acknowledges financial support from the Department of Defense through the National Defense Science and Engineering Graduate Fellowship program. D.C.H. and W.L.J acknowledge funding support through the Office of Naval Research. Author contributions: M.E.L., D.C.H., W.L.J., and R.O.R. designed research; M.E.L. and D.C.H. performed research; M.E.L., D.C.H, W.L.J., and R.O.R. analyzed data; and M.E.L., D.C.H., W.L.J., and R.O.R. wrote the paper. The authors declare no conflict of interest.

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August 21, 2023
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