Observation of shear localization through in-situ imaging under dynamic compression conditions*

Experimental tests at high strain-rates (>10³/s) often use measurement of shape change to infer flow stress behavior. In some extreme conditions, severe deformation of materials can lead to inhomogeneous intense zones of localized strain, typically called shear bands, serving as the precursor to failure. It has been observed in the past that some materials readily shear band under dynamic compression conditions. We performed a series of plate-impact hole closure experiments with in-situ X-ray radiography imaging to visualize the inhomogeneous response. Observed regions of sharp discontinuity indicate formation of shear banding in some materials while absent in others. Fully intact samples were recovered, and a series of post-mortem characterization is performed. Signatures in the in-situ imaging measurements will be discussed with relation to the post-mortem measurements and deviation from model predictions.