Recent advances in time-resolved imaging of impact-induced deformation of microprojectiles traveling at ~100 m/s to ~1 km/s have opened new and unique opportunities for studies of complex dynamic behavior of materials. When further augmented with computational modeling, a full-field interpretation of material mechanics and physics is feasible. This talk will survey three recent examples where the above nexus proves successful for (i) constitutive modeling of metallic materials, (ii) measurement of dynamic hardness of materials, (iii) developing process windows for kinetic deposition processes. In the first example, we resolve impact-induced deformation of metallic microparticles impacting rigid substrates. Linking real-time observations of plastic deformation to finite element simulations of impact, we show that we can accurately calibrate constitutive models in a relatively less explored regime of strain rates, i.e., beyond 10^6 per second. In the second example, we impact deformable metallic substrates with rigid microparticles. We use real-time measurements of impact and rebound velocities together with post-impact measurements of indentation volumes to determine dynamic hardness of materials at high strain rates. In the third example, we use time-resolved imaging and finite element simulations of deformable metallic microparticles impacting deformable metallic substrates to understand the transition from rebound regime to impact-bonding as impact velocity increases. We also reveal and discuss a second transition from impact-bonding to impact-erosion with further increase in impact velocity. The two transitions together define a processing window for kinetic deposition processes.
