Stronger glass products: Lessons learned and yet to be learned

Abstract

Potential for obtaining stronger glass products is discussed. Flaws, mostly forming‐ and handling‐generated and accelerated crack growth due to surrounding environment appear to give a strength distribution which is usually a factor of 500‐1000 less than the estimated theoretical strength. Contrary to traditional teachings emphasizing glass strength to be an extrinsic behavior, it is suggested that the atomic network topology determines the shear and hydrostatic yield strengths which are a precursor to the nucleation and growth of network cavitation, in turn, leading to generation of flaws and stress‐assisted growth starting from glass product‐forming processes. Hence, for stronger glass products, research is needed to develop fundamental understanding of the interrelationship between network topology, yield strengths, flaw cavitation and growth in molten glass as well as in solid glass as a function of glass composition and the complex stress fields around indents and impacts.

Toward hard and highly crack resistant magnesium aluminosilicate glasses and transparent glass‐ceramics

“…However, a following decrease in C R occurs when the heat-treated durations are further prolonged up to 15 hours. In addition, in contrast to the change in C R while similar to the evolution in H V , the densities of the present heat-treated magnesium aluminosilicate glasses exhibit a monotonic increase of 0.136 g/ cm 3 from 2.520 g/cm 3 for the as-prepared glass to 2.656 g/cm 3 for the one heat-treated for 15 hours.…”

“…As a widely used material, glass exhibits excellent optical properties and multifunctionalities, but its applications are limited by its low crack resistance due to the lack of large deformation or toughening mechanism at ambient temperature. [1][2][3] For most commercial glasses, the two properties, that is, hardness and crack resistance are not compatible. 4 Therefore, hard and tough glasses are particularly desired in many fields such as vehicles, civil engineering, and electronic devices.…”

3D microstructure and crack pathways of toughened CaO–Al2O3–SiO2 glass by precipitation of hexagonal CaAl2Si2O8 crystal

“…The low fracture toughness of oxide glasses is attributed to the lack of secondary phases and grain boundaries, which can prevent crack propagation. Once damage is generated on the surface, the glass is significantly weakened, thus leading to actual industrial problems . To avoid such problems, two kinds of tempered glasses, wherein compressive stress is built into the surfaces via rapid cooling or the ion exchange technique, are available for commercial applications, such as automotive and architectural windows, heat‐resistant tableware, cover glasses of handheld electric devices, and so on.…”

Indentation cracking and deformation mechanism of sodium aluminoborosilicate glasses

“…Therefore, it is essential to understand how the addition of various oxides in different proportions to silicate glasses will affect the properties of interest. In this regard, addressing the high brittleness and low fracture toughness of silicate glasses is essential …”

“…In this regard, addressing the high brittleness and low fracture toughness of silicate glasses is essential. [1][2][3][4][5] This tendency for brittle fracture experienced by oxide glasses is essentially a result of two phenomena. First, the inevitable formation of surface cracks throughout the lifetime of a glass product.…”