Precipitation of a metastable Fe(Ag) solid solution upon annealing of supersaturated Fe(Ag) thin film prepared by pulsed laser deposition

摘要

Upon annealing, a single-phase, bcc Fe_(1-x)Ag_x (x = 1.8 or 3.2 at. %) thin film, prepared by pulsed laser deposition, simultaneously undergoes grain growth and precipitation of a bcc Fe(Ag, 9-10 at. %) solid solution at the grain boundaries. At a high annealing temperature or after a long annealing time the metastable state transforms to the equilibrium state, pure Fe and pure Ag. A quantitative kinetic growth model has been proposed to explain that this non-equilibrium phenomenon results from surface diffusion.