A strain density function to analyze particle size effects during high velocity impacts of yttria

Abstract

AbstractThe impact behavior of a single yttria (Y2O3) nanoparticle onto a Y2O3 substrate is studied as a function of particle velocity (300–1200 m/s) and diameter (12–50 nm) using molecular dynamics simulations. To analyze the results, a strain density function is developed to provide both quantitative and qualitative information about the deformation mechanisms that contribute to the final state of the system. This function provides both clear evidence of shear localization and insight into the conditions for which localization occurs during the impact of Y2O3 particles as they approach experimentally relevant sizes. Further analysis shows that localization and fragmentation only occur for Y2O3 impacts with diameters of at least 50 nm, while particles with diameters of 25 nm and smaller deform primarily by amorphization and viscous flow. Implications for the deposition of films of Y2O3 and other rare‐earth oxides via the micro cold spray process are discussed.