Phase separation in undercooled molten Pd 80 Si 20 : Part I

摘要: Three different kinds of morphology are found in undercooled Pd80Si20, and they dominate at undercooling regimens ΔT, defined as ΔT = T1 – T k, where T 1 is the liquidus Pd80Si20 T k kinetic crystallization temperature. In small regimen, i.e., for ≤ 190 K, microstructures typically dendritic precipitation with a eutecticlike background. intermediate 220 spherical morphologies, which arise from nucleation growth, identified. addition, Pd particles throughout an entire specimen. large ≥ connected structure composed two subnetworks found. A sharp decrease dimension occurs to regimen. Although crystalline phases same, crystal growth rate too slow bring about occurrence grain refinement. Combining morphologies observed three their behaviors, we conclude that phase separation takes place molten Pd80Si20.