Phase Transformation in Nanoscale Indium-Tin Alloy Particles Embedded in Metallic Matrices

Abstract

The interfaces influence the phase stability of small particles. For embedded indium-tin alloy particles, the interface among the phases present within the particles and the matrix contribute significantly to the free energy and hence influences the phase stability at small sizes. Our results show that upon rapid cooling, we obtain a combination of larger two-phase alloy particles consisting of β- and γ-phases and very fine precipitates of In or Sn. Both β- and γ-phases possess an orientation relationship with Al. The in situ results suggest that the β-rich phase gradually dissolved in the eutectic liquid before melting and the particles retain the facets much above the melting temperature of the alloy particle. We have tried to explain the formation and stability of these phases in terms of favorable nucleation kinetics.