Structure and mechanical response of chemically strengthened aluminosilicate glass under different post-annealing conditions

The structure and mechanical response of chemically strengthened aluminosilicate glass under different post-annealing conditions were investigated. The structure and properties difference of chemically strengthened aluminosilicate glasses with air/vacuum post-annealing were discussed. IR spectrum, surface compressive stress, hardness, modulus, threshold load for radial crack initiation, and modulus of rupture were tested to characterize the surface structure and mechanical property changes of chemically strengthened glasses with different postannealing temperatures (250 degrees C, 300 degrees C, 350 degrees C, and 400 degrees C) and atmospheres (air and vacuum). Results demonstrate the following phenomena due to post-annealing temperature: Si-O-Si bond angle increases and quantities decrease; CS decreases and DOL increases; hardness and elastic modulus increase first and then decrease; threshold load for radial crack initiation and the flexural strength decrease. These changes in surface structure, CS and DOL, hardness and elastic modulus, and flexural strength are more evident in the vacuum atmosphere than in air. However, the glass with vacuum post-annealing shows a more temperature-dependent threshold load for radial crack initiation. The structure and mechanical response on the air side is different from that on the tin side. These results could provide technical guidance for the subsequent treatment process of chemically strengthened glasses.