The response of metals and their microstructures under extreme dynamic conditions can be markedly different from that under quasistatic conditions. Traditionally, high strain rates and shock stresses are achieved using cumbersome and expensive methods such as the Kolsky bar or large spall experiments. These methods are low throughput and do not facilitate high-fidelity microstructure–property linkages. In this work, we combine two powerful small-scale testing methods, custom nanoindentation, and laser-driven microflyer (LDMF) shock, to measure the dynamic and spall strength of metals. The nanoindentation system is configured to test samples from quasistatic to dynamic strain-rate regimes. The LDMF shock system can test samples through impact loading, triggering spall failure. The model material used for testing is magnesium alloys, which are lightweight, possess high-specific strengths, and have historically been challenging to design and strengthen due to their mechanical anisotropy. We adopt two distinct microstructures, solutionized (no precipitates) and peak-aged (with precipitates) to demonstrate interesting upticks in strain-rate sensitivity and evolution of dynamic strength. At high shock-loading rates, we unravel an interesting paradigm where the spall strength vs. strain rate of these materials converges, but the failure mechanisms are markedly different. Peak aging, considered to be a standard method to strengthen metallic alloys, causes catastrophic failure, faring much worse than solutionized alloys. Our high-throughput testing framework not only quantifies strength but also teases out unexplored failure mechanisms at extreme strain rates, providing valuable insights for the rapid design and improvement of materials for extreme environments.

The development of advanced materials for extreme dynamic environments requires an understanding of the links between the microstructure and the response of the material (i.e., Materials-by-Design). Spall failure significantly limits material performance at high strain rates, but our understanding of the influence of microstructure on spall strength is limited. While models suggest that increasing the static yield strength by adding precipitates or refining grain size can improve the spall strength, it is possible that the associated increase in nucleation sites may have deleterious effects on spall performance. Herein, we examine spall failure of a Magnesium-Aluminum system with precipitation and grain size strengthening through novel high-throughput laser-driven micro-flyer (LDMF) impact experiments. Six microstructures are investigated, four with grain sizes around 2–3 μm and precipitates around 0.5–1 μm, and two that are precipitate-free with grain sizes around 500 μm at six and nine percent Aluminum contents. The LDMF method allows us to detect differences in spall strength with relatively small changes in microstructure. The spall strength is observed to be strongly affected by varying levels of precipitates and consistently shows a notable reduction in average spall strength around 8–19% with the addition of precipitates, with values ranging from 1.22–1.50 GPa. The spall strength is also seen to decrease with the refinement of grain size independent of composition. However, this decrease is small compared to the hundred-fold grain size reduction. While ductile void growth is observed across all samples, greater variability and a further decrease in strength are seen with an increasing numbers of non-uniformly dispersed precipitates.