Abstract Scope |
Nanoindentation is a popular technique for investigating the mechanical properties of coatings and complex materials. Yet, it is usually limited to strain rates ≤ 0.1/s, which has long prevented investigating shock or collision conditions.
Several approaches have recently been proposed to overcome this technical limitation. On the one hand, nanoindentation impact tests yield strain rates > 105/s during a short transient. However, data evaluation is convoluted, and we will present evidence that the measured hardness might depend on the loading history.
For these reasons, constant strain rate indentation appears more desirable. The limitation to 0.1/s can be overcome with a newly introduced evaluation method discarding the need for a measurement of the contact stiffness. The presentation will focus on the current bottlenecks, which are the time constants of the hardware components, and present our latest results obtained with a piezo-based system optimized for high strain rates. |