A laser-driven high-strain-rate impact indentation test (LDIIT) instrument and its preliminary application for measuring the impact indentation characteristics of a Zr-based amorphous alloy

The micro/nano impact indentation test is an effective method for characterizing microscopic deformation and damage mechanisms of materials subjected to the impact load. Currently, micro/nano impact indentation test instruments predominantly utilize electromagnetic and pendulum driven principles. However, these driving mechanisms inherently limit the achievable strain rate to ∼104 s-1. To overcome this limitation and achieve a higher strain rate, this study developed a laser-driven high-strain-rate impact indentation test instrument with an impact unit as its core component. The instrument uses shock waves generated by laser-induced plasma explosion to drive the indenter to impact the specimen at an achievable strain rate of 105 s-1, and a high-speed camera was employed to in situ capture the impact process. First, the energy conversion component (including the elastic body, absorption layer, and constraint layer) in the impact unit was studied, and the influence of the component parameter on the impact velocity was analyzed. By experiments, the trend of impact velocity changes with component parameters was determined, and ultimately, active control of impact velocity was achieved. Then, the stability of the instrument was verified by impact tests on Al1050. After that, the impact indentation behaviors of a typical Zr-based amorphous alloy were characterized within the strain rate range of 3.36 × 104-2.62 × 105 s-1, which were comparatively analyzed with the quasi-static indentation characteristics. The findings verify the effectiveness of the laser-driven impact indentation test instrument and highlight the effects of high strain rates on the microscopic mechanical properties of materials.