Cleavage toughness of single crystals

TL;DR

This paper presents a new method based on Griffith's energy balance to predict the cleavage toughness, surface energy, and energy release rate of single crystals, aligning well with experimental data.

Contribution

It introduces a simple, bond-based definition of fracture parameters for single crystals, differing from traditional Irwin models, using complex variable functions for elastic modulus calculation.

Findings

Calculated cleavage toughness matches experimental values

Surface energy predictions are in excellent agreement with experiments

Method provides a concise tool for predicting fracture properties of crystals

Abstract

Griffith thermodynamic energy balance is employed to analyze cleavage phenomenon from atomic level. Results show that the cleavage toughness, the strain energy release rate, and the surface energy can be defined by the bond strength (the appropriate elastic modulus ) and the bond density. Such simple definition of fracture parameters is different from Irwin ones. This appropriate elastic modulus of single crystals is obtained using the complex variable function method. The calculated results of cleavage toughness and surface energy of typical ionic and covalent crystals by the present formulae are in excellent agreement with the experimental values. It demonstrates that our method offers a concise tool for predicting the cleavage toughness, the energy release rate and the surface energy of crystal cleavage planes.