Mechanical behavior of nanolaminates with alternating oxide layers

Abstract

By Griffith’s theory, the fracture strength of brittle materials reaches an ideal strength at a critical thickness. Also, metallic glass-metal nanolaminate composites had different mechanical behavior from metallic glass single layer, as reported by several authors: metal layers suppressed catastrophic failure of metallic glass. So here we look at the critical thickness of amorphous Al2O3 films, which are brittle materials, and the changes in the mechanical behavior of amorphous Al2O3 when it is laminated with the inorganic material. The push-to-pull tensile test was used here to measure mechanical properties of ultra-thin films. For sample preparation, Al2O3 films and other inorganic films were deposited using ALD and thin-films were fabricated with dog-bone shape using focused ion beam(FIB). We analyzed effect of thickness on mechanical properties and found the critical thickness of Al2O3 film. We then made amorphous Al2O3-inorganic nanolaminate composites and measured mechanical properties by tensile testing by an in-situ system.