Nanosecond timescale measurement of damage evolution in shock compressed magnesium alloy

Recent advances in ultra-fast X-ray imaging have enabled the real-time capture of damage evolution during spall failure using Synchrotron radiation. However, the fastest interval time is dictated by the bunch structure of the Synchrotron, typically in the hundreds of nanoseconds, often insufficient to examine incipient spall under shock. We reveal and track the evolution of dynamic tensile damage and failure through a combination of a novel target geometry and real-time X-ray phase-contrast imaging on the nanosecond timescale. By introducing a sloped free-surface, we spatially distribute release-wave interactions, thereby encoding time resolution in the spatial domain in 2D XPCI MHz sequences. As a consequence, each radiograph captures the progression of damage with a time resolution two orders of magnitude higher than conventional bunch dependent X-ray imaging. These results enable the kinetics of shock-induced void nucleation and coalescence to be directly measured and tracked, enabling visualisation of damage physics which has thus far eluded study, underpinning the development and validation of advanced spall failure models.