Small scale fracture mechanics of ductile materials: Advantage of fatigue precracks and comparison of J-integral evaluations

Abstract

Conducting fracture mechanics at small scales and extrapolating the behavior to larger length scales is a powerful tool to analyze materials and components with limited volumes of investigation. A critical requirement for this technique is the validity of the test methods at these scales on one hand, but also that the measured fracture mechanical quantities are independent of specimen size. To check whether the fracture toughness is size dependent we evaluated the fracture toughness of a ductile alloy at two length scales. Furthermore, we also investigated the influence of fatigue precracks compared to ion cut notches that are widely used at the micro scale.