Modeling Microstructural Evolution during Ballistic and Hypervelocity Impact in Aluminum Using Mesoscale Methods

The impact of a projectile at high velocity generates extreme pressures and temperatures upon a substrate, leading to localized deformation and complex microstructural phenomena. Depending on the impact velocity and projectile/substrate dimensions, this can lead to complex phenomena such as jetting, cratering, melting, projectile disintegration, and debris cloud formation. While experimental characterization techniques provide insights into these mechanisms, understanding microstructure evolution during these events is still unclear. A new mesoscale modeling method, quasi-coarse-grained dynamics (QCGD), enables the scaling of the capabilities of the classical molecular dynamics (MD) simulations to model microstructure evolution in systems with dimensions of tens of microns over timescales of hundreds of nanoseconds. This study demonstrates the applicability of QCGD simulations to investigate the microstructural evolution during the impact of Al projectiles with dimensions ranging from 20 - 100 microns to 10-micron-thick Al targets for impact velocities ranging from 3-7 km/s. QCGD simulations can reproduce jetting mechanisms at the projectile-substrate interface and localized melting shock propagation and investigate the thresholds that lead to projectile disintegration and the related evolution of the debris cloud. The QCGD framework, the evolution of pressure and temperature states, and microstructure evolution in various simulations will be presented.