Molecular-dynamics study of lattice-defect-nucleated melting in metals using an embedded-atom-method potential

Abstract

The high-temperature behavior of a high-angle twist grain boundary, a free surface, and planar arrays of voids of various sizes, all on the (001) plane in copper, are studied through molecular-dynamics simulation using an embedded-atom-method potential. Independently, we determine the thermodynamic melting point, ${T}_{m}$ of this potential through an analysis of the free energies of a perfect crystal and the liquid phase. It is found that an ideal crystal consisting of nearly 1000 atoms may be superheated over 200 K above ${T}_{m}$ while the introduction of any of the defects listed above nucleates melting at any temperature above ${T}_{m}$. We conclude that nucleation of the liquid phase at extrinsic defects is the most rapid, and therefore the dominant, mechanism of melting.