Mixed alkaline earth effect on nanomechanical properties of glass

The mixed alkaline earth effect (MAEE) on the mechanical behavior of oxide glasses have received significant attention of glass scientists. In this study, we unveiled the MAEE on the nanomechanical properties of a boroaluminosilicate (BAS) glass series with the varying molar ratios of R=[MgO]/([MgO]+[CaO]), through a combination of nanoindentation, nanoscratch, and nanowear tests. The MAEE was observed as positive deviations from the linear trend in nanohardness and reduced modulus with varying R. On the contrary, the MAEE manifested as negative deviations from the linear trend in nanoscratch depth, nanoscratch residual depth, nanowear volume, and volume densified by nanowear. The maximum and minimum values were observed at R = 0.56. The MAEE on nanowear behavior was found to be mainly governed by the nano-indentation and subsurface densification. These discoveries provide valuable insights into the nanomechanical properties of glass surfaces, contributing to the development of advanced glasses with improved mechanical properties and extended lifespans.