Solid-State Amorphization Observed in Ni-Sc System by Molecular Dynamics Simulation(Condensed matter: structure and mechanical and thermal properties)

概要

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An n-body potential of the Ni-Sc system is constructed under tight-binding formalism and the constructed potential is capable of reproducing some static and dynamic properties of the system. Applying the proven relevant Ni-Sc potential, molecular dynamics simulations are carried out using the solid solution and sandwich models. Simulations using the solid solution models not only reproduce the experimentally observed crystal-to-amorphous transition in the system, but also clarify that the physical origin of the transition is the crystalline lattice collapsing when the solute atoms are exceeding the critical solid solubilities. The critical solid solubilities are determined to be 18±2% Ni in the hcp Sc-based solid solutions and 20±2% Sc in fcc Ni-based solid solutions, which follows that the intrinsic glass-forming ability of the Ni-Sc system is within about 18-80% Ni, matching well with that observed in ion beam mixing experiments. Result of simulations using the Ni/Sc/Ni sandwich models indicate that the Ni-Sc amorphous layer at the interfaces grows in a layer-by-layer mode and the growth speeds towards the Ni and Sc lattices are approximately the same.
社団法人日本物理学会の論文
2006-08-15