Micromechanical properties of silicate glass films on sapphire substrates

摘要

The deformation of thin layers of glass on crystalline materials has been examined using newly developed experimental methods for nanomechanical testing. Continuous films of anorthite (CaAl_2Si_2O_8), celsian (BaAl_2Si_2O_8), and monticellite (CaMgSiO_4) were deposited onto Al_2O_3 surfaces by pulsed-laser deposition (PLD). Mechanical properties such as Yong's modulus and hardness were probed with a high-resolution depth-sensing indentation instrument. Nanomechanical testing, combined with AFM in-situ imaging of the deformed regions, allowed force-displacement measurements and imaging of the same regions of the specimen before and immediately after indentation. Emphasis has been placed on examining how changes in the glass composition, residual stress introduced into the films, effect of film's heat-treatment, and the effect of substrate crystallographic orientation will affect the mechanical properties of silicate-glass films.