Nanomechanical testing at high strain rates: New instrumentation for nanoindentation and microcompression

Abstract

Micromechanical testing is normally limited to the quasi-static strain rate regime: 10−5 to 10−2s−1. In this work, a nanomechanical testing device has been developed that allows indentation and microcompression at strain rates from the quasi-static regime continuously up to the high strain rate regime. To reach the highest strain rates, the conventional, strain gage-based load cell was replaced with a new piezo-based sensor. The sensor's concept, calibration methods, and measurement strategies are detailed. It is shown, using nanocrystalline Nickel as a case study material, that this new high strain rate device can measure precisely mechanical properties at strain rates up to 1000s−1 by nanoindentation, and strain rates up to 100s−1 by microcompression, enabling the device to measure strain rates over 9 orders of magnitude.