Initial crystallization in a nanostructured Al-Sm rare earth alloy

Date

2010-06-15

Author

Kalay, Yunus Eren
Chumbley, L. S.
Kramer, M. J.
Anderson, I. E.

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The transformation kinetics and microstructural evolution during initial crystallization in highly driven Al(90)Sm(10) were investigated using transmission electron microscopy (TEM). conventional Cu K(alpha) and high-energy synchrotron X-ray diffraction (HEXRD) and differential scanning calorimetry (DSC). The highest cooling rate obtained in this study yielded a high number density of fcc-Al nanocrystals, with sizes on the order of 2-5 nm, embedded in a disordered matrix rich in an Al-Sm medium range order (MRO) structure. Isothermal in-situ HEXRD results indicated a single crystallization of a large primitive cubic phase from the disordered state. Further analysis using DSC showed two crystallization events; a small peak overlapping the peak from the main crystallization event. TEM analysis performed at different stages of crystallization resolved pre-existing fcc-Al crystals, further crystallization of fcc-Al, (corresponding to the first small peak) and evolution of the cubic phase, corresponding to the main crystallization event. Fcc-Al nanocrystals showed a restricted growth and stayed at an average size of 16 nm after full crystallization was established. Transformation kinetics was described using Johnson-Mehl-Avrami approach after deconvolution of the overlapping crystallization peaks using a Gaussian approximation.

Subject Keywords

Materials Chemistry, Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Ceramics and Composites

URI

https://hdl.handle.net/11511/36010

Journal

JOURNAL OF NON-CRYSTALLINE SOLIDS

DOI

https://doi.org/10.1016/j.jnoncrysol.2010.05.005

Collections

Department of Metallurgical and Materials Engineering, Article

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Citation Formats

Y. E. Kalay, L. S. Chumbley, M. J. Kramer, and I. E. Anderson, “Initial crystallization in a nanostructured Al-Sm rare earth alloy,” JOURNAL OF NON-CRYSTALLINE SOLIDS, pp. 1416–1424, 2010, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36010.