Quasi-static Indentation Measurements: A Tool for Micro-mechanical Investigations of Interfaces in Polymer Materials
- The ongoing use of miniaturization, multi layer structure parts, and hybrid parts requires methods to determine mechanical properties on a micro scale. However, there is a gap in measuring techniques. On one hand there are the classical methods to measure hardness, e.g., Vickers, Rockwell, Universal, and IRHD, having resolutions typically above 100 µm. On the other hand, there are well-developed AFM methods that allow for the determination of mechanical properties in the nanometer range. This article describes an indentation technique that yields data of mechanical properties in the micrometer range between typically 5 and 50 µm. The measuring device and the data evaluation are presented. Results of micro-mechanical mapping are shown for NR-SBR rubber interfaces, a fuel tank, and a part manufactured by two-component injection molding. Finally, the measured micro-mechanical stiffness is compared to the Young's modulus of the corresponding materials.