Simulations of the melting of rare-gas inclusions in metals

Abstract

Molecular dynamics simulations are reported of the melting of small inclusions of rare gases in cavities 10-20 AA in radius in metals containing a few hundred gas atoms. Such systems enable the authors to study the melting phenomena of clusters of atoms constrained by the cavity walls. The authors have looked at the positions of the atoms, the phase diagrams, and the importance of fluctuations for bubbles of different sizes. Melting in these systems takes place over a finite temperature range as in simulations of isolated clusters. The geometric structure factors have been calculated and compared with recent X-ray diffraction measurements of Andersen et al. on krypton inclusions in aluminium. Their inability to reproduce the experimentally observed increase in the transverse diffraction peak width with temperature supports the suggestion of Andersen et al. that this increase is due to a roughening transition of the aluminium facets of the cavities.