The strain rate dependence of mechanical properties of materials, particularly at “high strain rates”, is of great interest for many applications including metal forming, machining, crashworthiness, projectile impact, etc. For strain rates above the quasi-static regime (>1 s−1), Split Hopkinson Pressure bar testing apparatus are most commonly used. While the uniaxial stress state in such experiments is desirable, the main drawbacks are the interference of elastic waves, low throughput, and extensive post processing of raw data. In view of these limitations, it is desirable to extend high strain rate capabilities of nanoindentation, thus taking advantage of relatively simple sample preparation, high-throughput testing capabilities and comparably small equipment.

This talk will focus on recent developments in instrumentation and testing protocols for high strain rate testing from 0.0001/s up to 20’000/s (8 orders of magnitude) with simultaneous high-speed actuation and sensing capabilities, with nanometer and micronewton resolution respectively. Moreover, we will elaborate on high strain rate testing performed at high and low temperatures as well as under variable humidity, and how the resulting multi-dimensional data is useful for understanding fundamental material behaviour and advancing engineering objectives. Specific case studies will include high strain rate nanoindentation at cryogenic temperatures and micro-compression experiments at elevated humidity. The challenges of such experiments and the associated technological and test protocol advances will be discussed along with select case studies.