Nano-impact indentation for high strain rate testing: The influence of rebound impacts

Abstract

Impact nanoindentation using a pendulum-based nanoindenter is an attractive technique for characterizing the high strain rate behavior of materials. However, pendulum-based systems typically allow the impacting indenter to strike multiple times as the pendulum rebounds and settles against the sample surface. This causes uncertainty as to whether the deformation is caused solely by the first impact or whether additional deformation occurs during the additional impacts. This work answers this question by using a modified system with a catching solenoid to prevent rebounding impacts. The difference in residual impressions made over a range of incident velocities between rebounding and single impacts is characterized using AFM. The rebounding impacts appear to be purely elastic and any additional deformation appears to be within the variability of the test.