Effect of interfacial segregation on phase decomposition of a thin film on a patterned substrate

Numerical simulations of phase decomposition in thin films on patterned substrates are presented for a binary alloy in order to study the influence of substrate composition on microstructural evolution. For systems with a substrate composition less than the film composition, a preferential segregation ofA to the interface was observed and no phase decomposition occurred within the film. For patterned systems with a substrate composition exceeding the film composition, theB-rich phase was able to grow by a barrierless transformation for a range of film compositions outside the chemical spinodal. The number of precipitates which formed on the mesa, the dihedral angles at the three-phase trijunctions, and the resulting microstructure within the film were shown to be sensitive to the substrate composition. This article is based on a presentation made in the 2002 Korea-US symposium on the “Phase Transformations of Nano-Materials,” organized as a special program of the 2002 Annual Meeting of the Korean Institute of Metals and Materials, held at Yonsel University, Seoul, Korea on October 25–26, 2002.