The limiting strength properties of nanocrystalline materials
Consideration is given to a number of exciting reasons for investigating the strength properties of ultrafine grain size materials, for example, as carefully pursued by J.R. Weertman and colleagues. One reason related to the increased importance of the interfacial energy versus volume free energy of crystals at nanoscale grain sizes, now suggested to connect with reported observations of greater grain boundary and grain volume disorder in molecular dynamics modeling of nanocrystalline material. A second reason relates to the proposed transition from grain volume deformation mechanisms to localized grain boundary shearing at the nanoscale, connecting with a number of predictions obtained from the dislocation pile-up model for the Hall-Petch (H-P) reciprocal square root of grain size dependence for strength values when small numbers of dislocations are present in the pile-ups. Model limitations on strength properties are described and an estimate is given of the local pile-up stress influence on Coble-type diffusional creep at nanocrystal boundaries.
- Research Organization:
- Univ. of Maryland, College Park, MD (US)
- Sponsoring Organization:
- US Department of the Navy, Office of Naval Research (ONR)
- OSTI ID:
- 20014220
- Resource Relation:
- Conference: 1999 TMS Fall Meeting, Julia R. Weertman Symposium: Advanced Materials for the 21st Century, Cincinnati, OH (US), 10/31/1999--11/04/1999; Other Information: PBD: 1999; Related Information: In: Advanced materials for the 21st century: The 1999 Julia R. Weertman symposium, by Chung, Y.W.; Dunand, D.C.; Liaw, P.K.; Olson, G.B. [eds.], 585 pages.
- Country of Publication:
- United States
- Language:
- English
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