Atomic scale study of the impact of metallic glass nanoparticles at high velocities

In this work we studied the high velocity impact of Cu ₄₅Zr ₄₅Al ₁₀ metallic glass nanoparticles onto substrates of the same material using molecular dynamics simulations. In particular we studied the effect of the impact velocity, nanoparticle temperature on the maximum penetration depth, damping coefficient, heat generated by the impact, and mechanical deformation. We observed that the velocity is the most important parameter affecting the impact behavior of the nanoparticle. A critical velocity was defined as the velocity required for the center of mass to remain just below the surface of the substrate. Mechanical deformation depended on this parameter. At values below the critical velocity, plasticity was almost negligible, while at values above, significant strains deep within both the substrate and the nanoparticle were observed, causing the latter to disintegrate completely. This deformation was accompanied by a relevant increase in liquid-like polyhedra as revealed by structural characterization based on Voronoi analysis.