Abstract Scope |
Nanoindentation is typically performed at strain rates < ~0.1/s, which precludes it from ballistic applications. Recent years have seen the development of nano-impact testing, which produces much higher deformation rates. However, data from such experiments are challenging to interpret, because the high strain rates are not sustained throughout the experiment.
Constant strain rate nanoindentation yields more meaningful data, albeit at the expense of the deformation velocity. The current limitation derives primarily from the plasticity error related to the continuous stiffness measurements (CSM). Here, we explore ways to push this limit by rewriting the standard Oliver-Pharr evaluation method, so as to avoid the need for a measurement of the contact stiffness, e.g. by CSM. With this improvement, the experimental upper strain rate limit is mostly determined by the time constants of the hardware components. A comparison between different commercially available systems will be presented. |