Theoretical Assessment of Thermodynamic Stability in Nanocrystalline Metallic Alloys

Surface Energies and Thermodynamic Phase Stability in Nanocrystalline Aluminas

Corundum, a-Al2O3, is the thermodynamically stable phase of coarsely crystalline aluminum oxide, but syntheses of nanocrystalline Al2O3 usually result in g-Al2O3. Adsorption microcalorimetry, thermogravimetric analyses, and Brunauer-Emmett-Teller adsorption experiments, coupled with recently reported high-temperature solution calorimetry data, prove that g-Al2O3 has a lower surface energy than ...

Nanocrystalline Soft Magnetic Alloys

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Surface Features of Nanocrystalline Alloys

Nanocrystalline alloys are prepared by controlled annealing of metallic glass precursors. The latter are obtained by rapid quenching of a melt on a rotating wheel. This process leads to structural deviation of the produced ribbons’ surfaces. Structural features of as-quenched and thermally annealed 57Fe81Mo8Cu1B10 ribbons were studied employing Conversion Electron Mössbauer Spectrometry (CEMS) ...

Oxidation Resistance of Nanocrystalline Alloys

Design of stable nanocrystalline alloys.

Nanostructured metals are generally unstable; their grains grow rapidly even at low temperatures, rendering them difficult to process and often unsuitable for usage. Alloying has been found to improve stability, but only in a few empirically discovered systems. We have developed a theoretical framework with which stable nanostructured alloys can be designed. A nanostructure stability map based ...