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

نویسندگان

  • Yifei Mo
  • Izabela Szlufarska
چکیده

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. © 2007 American Institute of Physics. DOI: 10.1063/1.2736652

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تاریخ انتشار 2007