Study on crack initiation and propagation in Li2O–Al2O3–SiO2 glass strengthened by different methods

Abstract

The study of fracture behavior in glass materials is of great significance for the service safety of engineering structures. This paper systematically investigates the effects of different strengthening methods: thermal tempering, ion exchange, and ceramization, on the microcrack initiation and propagation behavior of Li 2 O–Al 2 O 3 –SiO 2 (LAS) glass. Using Vickers indentation microhardness testing, three-dimensional topographical scanning via laser confocal microscopy, and ring-on-ring biaxial strength testing, the differences in crack initiation load, crack propagation rate, and dynamic crack propagation exponent ( n ) between strengthened and annealed glass (AG) were systematically analyzed. The results show that ion exchange glass (IEG) exhibits the highest crack initiation load (98 N) and the smallest crack extension, indicating that the deep compressive stress layer effectively suppresses crack initiation and propagation from surface microdefects. Glass-ceramic (GC) is prone to crack initiation under low loads, but the grain interlocking structure effectively limits further crack propagation. Thermal tempering glass (TTG) demonstrates a moderate strengthening effect, while AG shows the most significant crack initiation and propagation. Under both critical and higher loads, the apparent n values for LAS glass consistently followed the order IEG > TTG > GC > AG. Together with the time-dependent crack-growth observations, these results indicate that the surface compressive stress layer effectively suppresses subcritical crack growth.

The authors' abstract, as published at the source. Journal of Non-Crystalline Solids, 2026 · DOI ↗