Atomistic modeling of solid-state amorphization and atomic structure of the Cu–Hf system

Applied the newly constructed Cu–Hf potential, molecular dynamics simulations using Cu–Hf-Cu sandwich model showed that in the solid-state amorphization, the amorphous interlayer grew in a layer-by-layer mode and featured an asymmetric behavior. The growth of the amorphous interlayer advanced faster toward the Cu lattice than toward the Hf direction, closely relating to the higher cohesive energy of Hf than Cu. For the atomic configurations of the Cu65Hf35 metallic glasses, Voronoi tessellation analysis revealed that the dominating polyhedrons of Cu atoms were icosidihedron (CN = 13) and those of Hf atoms were icosioctahedron (CN = 16). The difference in CN could be attributed to the size difference, i.e., Hf has a larger atomic radius than Cu and therefore could accommodate more neighboring atoms.

► In the SSA of Cu–Hf system, amorphous interlayer grew in a layer-by-layer mode. ► The Cu–Hf amorphous interlayer featured an asymmetric behavior by MD simulation ► The growth of the amorphous interlayer advanced faster toward the Cu than Hf. ► The dominating polyhedrons for Cu were icosidihedron and for Hf were icosioctahedron. ► The atomic configurations were related to the size difference of the Cu and Hf atoms.