Quasi-ductile deformation of nanopores was studied by conducting nanoindentation tests on a consistent sample set of anodic aluminum oxide (AAO) membranes with varying porosity, interpore distances, and phases. The small feature size (wall thickness) of the nanoporous structure was identified as the key parameter to trigger and enhance nonbrittle, quasi-ductile nanopore deformations, regardless of material phase. With small wall thickness (

Keywords:alumina;deformation;fracture mechanics;toughness;nanomaterials;porous materials