Solid-State Alloying and Amorphization of Immiscible Elements

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9613865 Ma This research deals with metallic alloys that are far removed from equilibrium, namely amorphous alloys and supersaturated nanocrystalline solid solutions. The focus is on metastable phase formation using solid-state processing techniques in binary systems characterized by a large positive heat of mixing. A systematic experimental approach should lead to clearer understanding of the formation of metastable phases and their transformations in immiscible systems. Scientific areas explored include the mechanisms responsible for amorphization observed in some mechanically-alloyed binary immiscible systems; limitations to the extent of alloying in such systems; the degree of stability in these metastable phases; the degree of short range clustering; and the similarities and differences in thermodynamic behavior of immiscible alloys prepared through different solid-state techniques. Measurement techniques employed include calorimetry, transmission electron microscopy, thermodynamic modeling, and extended X-ray absorption fine structure analysis. %%% Development of the fundamentals of thermodynamic and kinetic phenomena of immiscible alloy systems is needed to understand their synthesis, structure, and stability. ***