Effect of Microscopic Structure on High-Cycle Fatigue Behavior in Nano-Components

Abstract

In order to investigate the effect of microscopic structure on fatigue behavior of nanoscale components, a resonant fatigue experiment is conducted using a nanocomponents specimen where the test section is composed of a single crystalline Si substrate, a 200 nm thickness Cu polycrystalline film and a SiN amorphous layer. In the specimen, only the Cu portion plastically deforms because the yield stress is lower than those of other materials. The shape and the crystalline orientation of each grain on the surface of Cu portion are specified by means of EBSD. Although crystallographic slip bands with a width of a few tens of nanometers appear only in a grain of Cu portion, the grain is different from that expected by the Schmid factor. A FEM analysis, which takes into account the deformation anisotropy of grains, reveals that shear stress to generate slip bands is concentrated on the grain owing to the deformation constraint by neighboring crystals and components.