| Abstract
| - Bimetallic particles have two features not observed in one-component systems: surface segregation andcompositional ordering. Molecular dynamics simulations have been performed to study the freezing of Ni−Al nanoclusters at different compositions. It was found that for Al-rich and equiatomic compositions thesurface segregation of Al atoms inhibits nucleation, causing supercooled clusters to solidify to an amorphousaggregate. In the case of Ni3Al particles, where there are not enough Al atoms to complete the surface layer,clusters froze to multiply twinned structures with well-defined local translational order but, owing to the fastkinetics of solidification, with compositional disorder.
|
