Small-angle x-ray-scattering study of phase separation and crystallization in the bulk amorphousMg62Cu25Y10Li3alloy
| Autor: | S. Schneider, William L. Johnson, U. Geyer, Wing Kam Liu, Pappannan Thiyagarajan |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
010302 applied physics
Amorphous metal Materials science Annealing (metallurgy) Small-angle X-ray scattering Analytical chemistry 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Nanocrystalline material Amorphous solid law.invention Differential scanning calorimetry law Phase (matter) 0103 physical sciences Crystallization 0210 nano-technology |
| Zdroj: | Physical Review B. 59:11755-11759 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.59.11755 |
| Popis: | We report on a small-angle x-ray-scattering (SAXS) and differential scanning calorimetry study of phase separation and crystallization in rapidly quenched amorphous Mg62Cu25Y10Li3 alloy samples. Differential scanning calorimetry demonstrates the occurrence of crystallization and grain growth upon isothermal annealing of these samples at 135 °C. The SAXS studies show the presence of large inhomogeneities even in the rapidly quenched as-prepared Mg62Cu25Y10Li3 alloy that is attributed to phase separation in the undercooled liquid during the cooling process. After isothermal annealing at 135 °C for longer than 30 min the samples exhibit a strong SAXS intensity that monotonically increases with increasing annealing time. During heat treatment, crystallization and growth of a nanocrystalline bcc-Mg7Li3 phase occurs in the Y-poor and MgLi-rich domains. The initially rough boundaries of the nanocrystals become sharper with increasing annealing time. Anomalous small-angle x-ray-scattering investigations near the Cu K edge indicate that while Cu is distributed homogeneously in the as-prepared sample, a Cu composition gradient develops between the matrix and the bcc-Mg7Li3 nanocrystals in the annealed sample. |
| Databáze: | OpenAIRE |
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