Molecular dynamics simulations have been employed to study the thermodynamic stability of nanometersized Ag50Cu50 spherical particles with radius in the range between 1 and 10 nm. Four different structural arrangements of Ag and Cu atoms were considered, namely an unmixed phase in which Ag and Cu are separated by a coherent interface, two core-shell systems with Ag shells and Cu cores and vice versa and a perfect random solid solution. All of these cases share the same crystallographic arrangement of atoms but a different chemical order. Free-energy differences between the unmixed phase and the other ones were estimated according to the Bennett’s method. It is shown that free-energy differences scale inversely with the particle radius. The results obtained also provide information on fundamental thermodynamic properties such as surface and interface free energies.
Free energy differences between Ag-Cu nanophases with different chemical order
DELOGU, FRANCESCO
2010
Abstract
Molecular dynamics simulations have been employed to study the thermodynamic stability of nanometersized Ag50Cu50 spherical particles with radius in the range between 1 and 10 nm. Four different structural arrangements of Ag and Cu atoms were considered, namely an unmixed phase in which Ag and Cu are separated by a coherent interface, two core-shell systems with Ag shells and Cu cores and vice versa and a perfect random solid solution. All of these cases share the same crystallographic arrangement of atoms but a different chemical order. Free-energy differences between the unmixed phase and the other ones were estimated according to the Bennett’s method. It is shown that free-energy differences scale inversely with the particle radius. The results obtained also provide information on fundamental thermodynamic properties such as surface and interface free energies.
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