Small-angle x-ray-scattering study of phase separation and crystallization in the bulk amorphous Mg{sub 62}Cu{sub 25}Y{sub 10}Li{sub 3} alloy
- W. M. Keck Laboratory of Engineering Materials, 138-78, California Institute of Technology, Pasadena, California 91125 (United States)
- I. Physikalisches Institut and Sonderforschungsbereich 345, Universitaet Goettingen, D-37073 Goettingen (Germany)
- Intense Pulsed Neutron Source Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
We report on a small-angle x-ray-scattering (SAXS) and differential scanning calorimetry study of phase separation and crystallization in rapidly quenched amorphous Mg{sub 62}Cu{sub 25}Y{sub 10}Li{sub 3} alloy samples. Differential scanning calorimetry demonstrates the occurrence of crystallization and grain growth upon isothermal annealing of these samples at 135{degree}C. The SAXS studies show the presence of large inhomogeneities even in the rapidly quenched as-prepared Mg{sub 62}Cu{sub 25}Y{sub 10}Li{sub 3} alloy that is attributed to phase separation in the undercooled liquid during the cooling process. After isothermal annealing at 135{degree}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-Mg{sub 7}Li{sub 3} 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 {ital 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-Mg{sub 7}Li{sub 3} nanocrystals in the annealed sample. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 348205
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 59, Issue 18; Other Information: PBD: May 1999
- Country of Publication:
- United States
- Language:
- English
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