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Article Dans Une Revue Journal of Non-Crystalline Solids Année : 2016

Deformation of silica glass studied by molecular dynamics: Structural origin of the anisotropy and non-Newtonian behavior

Xavier Bidault
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Stéphane Chaussedent
Daniel R. Neuville

Résumé

A novel aspect of the medium-range structure of silica drawn into fibers is studied. The network of silica glass structure is composed of corner-shared SiO 4 tetrahedra, and it can be seen as a structure of interconnected rings (Si-O) n of various size, denoted nMR (n-Membered Ring). Molecular Dynamics simulations show that small-sized silica rings get a preferential orientation during the drawing, either during the high-temperature stage for 3MR, or during the cooling for 4MR and 5MR, and they persist in this state in the fiber at ambient temperature. This leads to a structural anisotropy, more specifically a " transverse isotropy " , because of different longitudinal and transversal physical properties. This anisotropic structural rearrangement during the drawing process induces a non-Newtonian behavior of the modeled glass melt, with strain-rate dependent properties. Highlights: Anisotropy in silica glass comes from the orientation that small silica rings acquire during the deformation. The model is in agreement with experiments (non-Newtonian behavior of the melt, anisotropic elasticity of the fiber). The anisotropy in silica fiber is a " transverse isotropy " .
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Dates et versions

hal-01351452 , version 1 (03-08-2016)

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Xavier Bidault, Stéphane Chaussedent, Wilfried Blanc, Daniel R. Neuville. Deformation of silica glass studied by molecular dynamics: Structural origin of the anisotropy and non-Newtonian behavior. Journal of Non-Crystalline Solids, 2016, ⟨10.1016/j.jnoncrysol.2015.11.029⟩. ⟨hal-01351452⟩
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