Hardness and fracture toughness are some of the most important mechanical properties. Here, we propose a simple model that uses only the elastic properties to calculate the hardness and fracture toughness. Its accuracy is checked by comparison with other available models and experimental data for metals, covalent and ionic crystals, and bulk metallic glasses. We found the model to perform well on all datasets for both hardness and fracture toughness, while for auxetic materials (i.e., those having a negative Poisson’s ratio), it turned out to be the only model that gives reasonable hardness. Predictions are made for several materials for which no experimental data exist.

Topics
First-principle calculations, Metallic solids, Elastic modulus, Fracture mechanics, Hardness, Mechanical properties, Bulk modulus, Poisson's ratio, Shear modulus, Superhard materials
© 2019 Author(s).
2019
Author(s)
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