On the relationship between ideal tensile strength and surface energy

Abstract

Estimates of the ideal uniaxial tensile strength are frequently made by means of an equation proposed initially by Orowan and Polanyi. This equation relates the ideal strength to the elastic modulus, surface energy and lattice parameter. Previously we have used the Born-Mayer and Lennard-Jones potential models to calculate each of these quantities separately, for sodium chloride and argon respectively. Hence we are able to make a test of the validity of the Orowan-Polanyi equation when applied to these materials. In all cases we find that this equation overestimates the ideal strength by a factor of 2–4 x.