Download the full version of the article (in PDF format)

O. V. Savvova, O. I. Fesenko, H. K. Voronov, S. O. Riabinin
«Features of the Formation of Nanostructure in Lithium-Aluminium-Silicate Glass–Ceramic Materials at the Initial Stages of Nucleation»
0889–0902 (2020)

PACS numbers: 61.46.-w, 68.35.Rh, 68.37.-p, 68.55.A-, 68.55.Nq, 81.10.Dn, 81.70.Pg

The prospect of design of the nanostructured glass–ceramic materials from the standpoint of self-organization of dissipative structures is analysed. The feasibility of developing lithium-aluminium-silicate glass–ceramics in the fabrication of highly effective elements of protective structures is established. The importance of regulating the material nanostructure at the nucleation stage when high-strength glass–ceramic materials are created is determined. The criteria for the development of glass matrices are selected; the choice of composition and crystallization catalysts in the fabrication of glass–ceramic materials to protect special equipment is justified. Model glasses and materials based on them are synthesized, and the optimal compositions for the fabrication of glass–ceramic materials with a definite level of light transmission and the type of crystallization using glass and ceramic technologies are selected. The phase-formation features of the obtained glasses after melting and during the heat treatment are revealed. They consist in the formation of fluctuations and incipient of lithium metasilicate crystals with the subsequent formation of finely dispersed mass devitrification materials’ structures during heat treatment. The features of the nanostructure formation for developed lithium-aluminium-silicate glasses at the initial stages of nucleation are investigated. The mechanism of structure formation of lithium-aluminium-silicate glasses during heat treatment is established. It consists in the following sequential processes: the formation of sibotaxic groups in the glass melt, followed by the formation of nanoscale grain crystallization due to phase separation; the behaviour of self-organization of the structure with the formation of both lithium disilicate crystals with a size of 0.4 µm in an amount of 50 vol.% and \(\beta\)-spodumene with a size <1 µm in an amount of 85 vol.% that is the key to their high strength and light transmission. For the developed glass–ceramic materials based on lithium-aluminium-silicate glasses, the formation of a dissipative metal structure using the phase-separation mechanism under conditions of low-temperature heat treatment allows their high performance properties (H=8.9–9.0 GPa, HV=8.74–8.9 GPa, K\(_{1C}\)=3.10–3.40 MPa⋅m\(^{1/2}\)) to be ensured. This allows us to consider them promising when creating structures for the protection of special equipment.

Keywords: lithium aluminosilicate glass–ceramic materials, nanosize dissipative structure, grain of crystallization, phase separation, mechanical characteristic