SKM 2023 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 9: Topical Session: Fundamentals of Fracture – Interface Fracture
MM 9.6: Talk
Monday, March 27, 2023, 17:30–17:45, SCH A 216
Characterizing interface toughness in functional materials — •Eloho Okotete1, Subin Lee1, Steffen Brinckmann2, and Christoph Kirchlechner1 — 1Institute for Applied Materials, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany — 2Structure and Function of Materials (IEK-2), Forschungszentrum Jülch, 52425 Jülich, Germany
Interfaces are the backbones of functionality in emerging material systems for this new age. However, mechanical failure usually occurs in these interfaces leading to degradation of functional properties. Experimental methods to investigate the interface strength and its failure mechanisms include peel test, super layer test, or indentation test. These methods output qualitative data with huge experimental scatter and a lack of in-depth understanding of underlying mechanisms of failure. Small-scale mechanical testing using single and double cantilever beams makes it possible to extract quantitative data for interface properties of micro/ nanometer-sized films. However, these methods are prone to unstable crack growth, finite notch root radius, and other problems arising from testing geometries. In this talk, we propose a new micro cantilever design that provides reliable quantitative interface toughness. Our initial finite element calculations showed the optimized geometry could propagate a pre-notch in a stable manner, which is essential to generate a natural crack front without FIB-induced damage/artifacts. This observation is validated with in situ experiments on the interface between a hard coating and silicon substrate.