Effect of Densification Treatment on the Mechanical Properties of Borate Glasses

Abstract

Densified alkali borate glasses were prepared by applying hydrostatic pressure up to 6GPa near the glass transition temperature. The mechanical properties such as Young's modulus and hardness were measured. The yield stress for 5Na₂O·95B₂O₃ and 10Na₂O·90B₂O₃ glasses was calculated from the interference fringes of the indented surface. Young's modulus and Knoop hardness increased with an increase of the degree of densification. The yield stress increased and tended to approach a constant value with the densification. These variations with densification were explained by the decrease of void and the increase of two-dimensional structural groups in glass network.