Mechanical properties and deformation mechanism of Al2O3 determined from in situ transmission electron microscopy compression

The mechanical properties and deformation mechanism of alumina (Al2O3) ceramic nanopillars and microstructures have been studied using in situ transmission electron microscopy (TEM) compression and nanoindentation experiments. It has been found that the Young's modulus of Al2O3 nanopillars significantly increases with a decrease of its thickness; it ranges from 54.8 GPa for the nanopillar of radius 175 nm to 347.5 GPa for the one of radius of 75 nm. The hardness of Al2O3 microstructures estimated by the nanoindentation is between 3.19 to 20.60 GPa. The Raman spectra of Al2O3 substrate has a production peak (577.3 cm(-1)) between 418.3 and 645.2 (cm(-1)) peaks. The strain hardening behavior of Al2O3 microstructures has been observed and the impact of size on the compressive and bending behavior of Al2O3 micro-pillared structures is also examined and explained.