Simple and accurate model of fracture toughness of solids

TL;DR

This paper presents a universal, first-principles-based model to predict the fracture toughness of various solids, including covalent, ionic, metallic, and intermetallic materials, with good experimental agreement.

Contribution

The authors develop a universal fracture toughness model incorporating an enhancement factor based on electronic properties, enabling accurate predictions from first-principles calculations.

Findings

Model accurately predicts fracture toughness for multiple materials.

Parameters are obtainable from first-principles calculations.

Good agreement with experimental data across material types.

Abstract

Fracture toughness $K_{IC}$ plays an important role in materials design. Along with numerous experimental methods to measure fracture toughness of materials, its understanding and theoretical prediction is very important. However, theoretical prediction of fracture toughness is challenging. By investigating the correlation between fracture toughness and elastic properties of materials, we have constructed a fracture toughness model for covalent and ionic crystals. Furthermore, by introducing an enhancement factor, which is determined by the density of states at the Fermi level and atomic electronegativities, we have constructed a universal model of fracture toughness for covalent and ionic crystals, metals and intermetallics. The predicted fracture toughnesses are in good agreement with experimental values for a series of materials. All the parameters in the proposed model of fracture toughness can be obtained from first-principles calculations, which makes it suitable for practical applications.