Solute-derived Thermal Stabilization of Nano-sized Grains in Melt-Spun Aluminum

Published

June 2, 2016

Author(s)

Andrew H. Baker, Paul G. Sanders, Eric Lass, Deepak Kapoor, Steve L. Kampe

Abstract

Thermal stability of nanograined metals can be difficult due to the large driving force for growth that arises from the significant boundary area constituted by the nanostructure. Kinetic approaches for stabilization of the nanostructure effective at low homologous temperatures often fail at higher homologous temperatures. Thermodynamic approaches for thermal stabilization may offer higher temperature stability. In this research, modest alloying of aluminum with solute (mole fraction of Sc, Yb, or Sr of 1 %) was examined as a means to thermodynamically stabilize a bulk nanostructure at elevated temperatures. Following 1 h annealing treatments at 673 K (0.6 Tm), 773 K (0.75 Tm), and 873 K (0.9 Tm), the alloys remain nanocrystalline (<100 nm) as measured by Warren-Averbach Fourier analysis of x-ray diffraction peaks and direct observation of TEM dark field micrographs, with the efficacy of stabilization: Sr>Yb>Sc. Disappearance of intermetallic phases in the Sr and Yb alloys in the x-ray diffraction spectra are observed to occur coincident with the stabilization after annealing, suggesting that precipitates dissolve and the boundaries are enriched with solute.

Citation

Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science

Pub Type

Journals

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Keywords

melt-spinning, nanocrystalline, aluminum, thermal stability, rapid solidification

Citation

Baker, A. , Sanders, P. , Lass, E. , Kapoor, D. and Kampe, S. (2016), Solute-derived Thermal Stabilization of Nano-sized Grains in Melt-Spun Aluminum, Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=916192 (Accessed April 18, 2024)