Size effect in strength measuring of inorganic glasses

The paper presents the results of the study of three-component glass viscoelastic properties using micro- and nanoindentation methods. The purpose of the research is to confirm experimentally the dependence of the strength characteristics of glass on the size of the deformation area at various temperatures. The object of the study was a glass sample composed of SiO₂ (60 %), B₂O₃ (20 %), and SrO (20 %). The experiments were conducted on the Nanotest 600 complex at temperatures ranging from 20 to 500 °C using Berkovich indenter. Additionally, microhardness measurements were made using ITV-1-AM device. The main results demonstrated significant influence of deformation area size on the material strength characteristics. When indentation depth is less than 1 μm, a considerable increase in material hardness is observed due to the change from dislocation deformation mechanisms to diffusion ones. At room temperature, the nanohardness value (9 GPa) significantly exceeds the microhardness indicator (6 GPa).