High toughness transparent glass‐ceramics with petalite and β‐spodumene solid solution as two major crystal phases
Ye Luo, Conghang Qu, John C. Mauro
Abstract
Abstract Lithium aluminosilicate glass‐ceramics are well known for good transparency, high fracture toughness, low thermal expansion, and good ion exchange ability. In this study, new transparent Li 2 O‐Al 2 O 3 ‐SiO 2 (LAS) glass‐ceramics with petalite and β‐spodumene solid solution as the major crystalline phases were invented for favorable mechanical properties and potential for application in the hollowware, tableware, container, and plate glass industries. Crystal phases are mainly influenced by the ratio of Al 2 O 3 to SiO 2 concentrations. The concentration of SiO 2 required to form specific crystalline phases in the glass‐ceramics is higher than that inferred from the ternary phase diagram. Al 2 O 3 content is required to be sufficiently high for the formation of crystals, instead of balancing excess amounts of Li 2 O in the glass. The average transmittances of 2.0 ± 0.1 mm thickness samples in visible light regions (400–700 nm) can reach more than 80% with crystal sizes of 20–40 nm. Transmittance is significantly decreased for heat treatments around 710°C, due to the high growth rate of β‐spodumene solid solution crystals. Vickers hardness, indentation toughness, and crack probabilities of transparent LAS glass‐ceramics are significantly improved compared with standard soda lime silicate glass, due to the crack bridging and deflection of crystal grains.