Composition-dependent mechanical property changes in Au-ion-irradiated borosilicate glasses

Abstract

The mechanical property changes in three kinds of ternary borosilicate glasses (named NBS glasses) induced by 8.0-MeV Au3+ were studied by nanoindentation measurements. For these borosilicate glasses, the molar ratio R = [Na2O]/[B2O3] is varied (1.34, 0.75, and 0.40 for NBS1, NBS2, and NBS3, respectively), while their molar ratio K = [SiO2]/[B2O3] is fixed at 4.04. The nanoindentation results indicate that both the hardness and reduced Young modulus were decreased after irradiation. No obvious difference in both hardness and modulus variations of these three NBS glasses was observed. Based on the main structures of their pristine samples, the reedmergnerite groups containing Si-O-BIV may be the structural origin of Au-ion-irradiated mechanical property changes in the homogeneous glasses with R > 0.5. However, the modification of the silica network and phase separation may dominate the mechanical property changes for glasses with R ≤ 0.5. The ion- and electron-irradiation-induced mechanical property changes of these NBS glasses were also compared in this study. The extended incubation dose and the slower decreasing rate can be observed in electron-irradiation-induced hardness and modulus variations, which may be caused by the different mechanisms between both irradiation scenarios.