ATOMISTIC CONSIDERATIONS ON THE FRACTURE-TOUGHNESS OF BRITTLE MATERIALS

A simple atomistic approach to the mechanical strength and the fracture toughness of brittle materials is made by the use of a universal expression for binding potential energy versus atomic separation curves. The scaling factors for the atomic separation and for the energy amplitude successfully apply to describing the intrinsic fracture toughness K* in a scaled dimensionless form. It is demonstrated that the intrinsic fracture toughness combined with a stress shielding coefficient (SSC) yields the fracture toughness of real materials. Microfracture mechanisms for crack-tip stress-shielding processes, as well as the interrelationship between the stress intensity- and the potential energy-derived fracture toughness, are addressed.