Fracture toughness of nanostructured silicon carbide

By using atomistic simulations, we derive a constitutive equation for a microfractured beta-SiC matrix containing hard or soft inclusions. The proposed equation is shown to follow the Eshelby theory for elastic inclusions, and appears to hold for any crack tip-inclusion distance and for a wide range of values of matrix-inclusion elastic mismatch. A comparison of the atomistic results with existing continuum elasticity models points out the weaknesses of some commonly adopted simplifying assumptions. (C) 2005 American Institute of Physics.