2024-01-12 オークリッジ国立研究所(ORNL)
◆特に、珪酸ガラスでは中距離原子環の構造と液体の脆弱性との間に明確な相関があり、これがガラスの設計と製造に影響を与える可能性があります。研究は、ガラスの遷移温度範囲とその構造的特徴の関連性を示し、これがガラスの性能特性に影響を与えることを明らかにしました。
＜関連情報＞
- https://www.ornl.gov/news/corning-neutron-research-nomad
- https://www.nature.com/articles/s41467-022-35711-6
ケイ酸塩ガラスにおける液体の脆弱性と中距離秩序の関係を明らかにする Revealing the relationship between liquid fragility and medium-range order in silicate glasses
Ying Shi,Binghui Deng,Ozgur Gulbiten,Mathieu Bauchy,Qi Zhou,Jörg Neuefeind,Stephen R. Elliott,Nicholas J. Smith & Douglas C. Allan
Nature Communications Published:03 January 2023
DOI:https://doi.org/10.1038/s41467-022-35711-6
Abstract
Despite decades of studies, the nature of the glass transition remains elusive. In particular, the sharpness of the dynamical arrest of a melt at the glass transition is captured by its fragility. Here, we reveal that fragility is governed by the medium-range order structure. Based on neutron-diffraction data for a series of aluminosilicate glasses, we propose a measurable structural parameter that features a strong inverse correlation with fragility, namely, the average medium-range distance (MRD). We use in-situ high-temperature neutron-scattering data to discuss the physical origin of this correlation. We argue that glasses exhibiting low MRD values present an excess of small network rings. Such rings are unstable and deform more readily with changes in temperature, which tends to increase fragility. These results reveal that the sharpness of the dynamical arrest experienced by a silicate glass at the glass transition is surprisingly encoded into the stability of rings in its network.
