Revisiting the Dependence of Poisson’s Ratio on Liquid Fragility and Atomic Packing Density in Oxide Glasses
oleh: Martin B. Østergaard, Søren R. Hansen, Kacper Januchta, Theany To, Sylwester J. Rzoska, Michal Bockowski, Mathieu Bauchy, Morten M. Smedskjaer
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2019-07-01 |
Deskripsi
Poisson’s ratio (<i>ν</i>) defines a material’s propensity to laterally expand upon compression, or laterally shrink upon tension for non-auxetic materials. This fundamental metric has traditionally, in some fields, been assumed to be a material-independent constant, but it is clear that it varies with composition across glasses, ceramics, metals, and polymers. The intrinsically elastic metric has also been suggested to control a range of properties, even beyond the linear-elastic regime. Notably, metallic glasses show a striking brittle-to-ductile (BTD) transition for ν-values above ~0.32. The BTD transition has also been suggested to be valid for oxide glasses, but, unfortunately, direct prediction of Poisson’s ratio from chemical composition remains challenging. With the long-term goal to discover such high-ν oxide glasses, we here revisit whether previously proposed relationships between Poisson’s ratio and liquid fragility (<i>m</i>) and atomic packing density (<i>C</i><sub>g</sub>) hold for oxide glasses, since this would enable <i>m</i> and <i>C</i><sub>g</sub> to be used as surrogates for <i>ν</i>. To do so, we have performed an extensive literature review and synthesized new oxide glasses within the zinc borate and aluminoborate families that are found to exhibit high Poisson’s ratio values up to ~0.34. We are not able to unequivocally confirm the universality of the Novikov-Sokolov correlation between <i>ν</i> and <i>m</i> and that between <i>ν</i> and <i>C</i><sub>g</sub> for oxide glass-formers, nor for the organic, ionic, chalcogenide, halogenide, or metallic glasses. Despite significant scatter, we do, however, observe an overall increase in <i>ν</i> with increasing <i>m</i> and <i>C</i><sub>g</sub>, but it is clear that additional structural details besides <i>m</i> or <i>C</i><sub>g</sub> are needed to predict and understand the composition dependence of Poisson’s ratio. Finally, we also infer from literature data that, in addition to high <i>ν</i>, high Young’s modulus is also needed to obtain glasses with high fracture toughness.