The stability of the β-phase of tantalum: a molecular dynamics study

Abstract

Molecular dynamics simulations have been performed on tantalum clustersusing the embedded-atom-method potential. Melting simulations show thatβ-Ta clusters have a lower melting temperature than the same size clusters ofα-Ta (bccstructure). Pure β-Ta clusters are quite stable and do not transform to theα-Ta on melting. Simulations on Ta clusters with mixedα- andβ-phases reveal that inclusion of a bcc-Ta cluster within aβ-Ta clusterinduces the β-to-α-phase transformation at a temperature far below the melting point of a pureβ-Ta cluster, depending on the cluster size andα-to-β-atom ratio. The results suggest that the observed phase transformation ofβ-Ta thin films is dueto the presence of α-phase inclusions in the β-Ta film grains.