Simultaneous enhancement of toughness, ductility, and strength of nanocrystalline ceramics at high strain-rates

Journal Article · Mon Apr 30 04:00:00 EDT 2007 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2736652· OSTI ID:20971901

Yifei, Mo; Szlufarska, Izabela ^[1]

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1. Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States)

Molecular dynamics simulations of tensile testing have been performed on nc-SiC. Reduction of grain size promotes simultaneous enhancement of ductility, toughness, and strength. nc-SiC fails by intergranular fracture preceded by atomic level necking. Conventionally, high strain-rate deformations of ceramics are limited by diffusion time scales, since diffusion prevents premature cavitation and failure. The authors report a nondiffusional mechanism for suppressing premature cavitation, which is based on unconstrained plastic flow at grain boundaries. Based on the composite's rule of mixture, they estimate Young's modulus of random high-angle grain boundaries in nc-SiC to be about 130 GPa.

• OSTI ID: 20971901
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 18 Vol. 90; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CAVITATION
CERAMICS
CRYSTALS
DEFORMATION
DUCTILITY
FRACTURE PROPERTIES
FRACTURES
GRAIN BOUNDARIES
GRAIN SIZE
MOLECULAR DYNAMICS METHOD
NANOSTRUCTURES
PRESSURE RANGE GIGA PA
RANDOMNESS
SILICON COMPOUNDS
SIMULATION
STRAIN RATE
YOUNG MODULUS