Interatomic bond energy and analytical scale of hardness

Abstract

Based on detailed models of interatomic cohesion and the well-developed structural-thermodynamic approach, the interatomic bond energy has been determined for some covalent and metallic crystals and it has been found to agree with experimental data. Using the proposed analytical relationship for the degree of covalency of crystals the author has elaborated a generalized model that describes experimental hardness of supersclerometer materials (diamond, cBN, SiC, and others), minerals, refractory compounds, semiconductors, ionic crystals and metals. On the basis of the mechanical-chemical approach to (nano)flow a dislocation model of crystal-mechanical anisotropy of yield strength has been put forward for monocrystalline diamond and lonsdaleite; the model makes it possible to draw a conclusion on a slight difference in their sclerometric characteristics. The experimental relationships that govern high-temperature high-pressure plasticity in some covalent crystals are discussed.