Ductile-to-Brittle Transition in Nanocrystalline Metals

Authors

  • H. Li,

    1. Department of Materials Science and Engineering, University of Florida, P.O. Box 116400, Gainesville, FL 32611(USA)
    2. Present address: Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA.
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  • F. Ebrahimi

    1. Department of Materials Science and Engineering, University of Florida, P.O. Box 116400, Gainesville, FL 32611(USA)
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  • This study was supported by the National Science Foundation under grant No. DMR-9980213. We thank the Major Analytical Instrumentation Center (MAIC) at the University of Florida, particularly Mr. G. Bourne for helping with the FIB system.

Abstract

original image

Fracture in nanocrystalline metals is shown to depend on grain size. If the grain size is large enough, nanocrystalline metals fracture with a similar mechanism to coarse-grained materials—with extensive reduction in area and a ductile mode. Grain sizes below a critical value result in brittle fracture, via the breaking of atomic bonds (see Figure and cover). On the nanoscale, the cracks follow a mainly intergranular path.

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