Anomalous grain refinement trends during mechanical milling of Bi2Te3
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Author(s) •
Humphry-Baker, Samuel A
Schuh, Christopher A
Date Issued
June 2014
Journal
Acta Materialia
Publisher
Elsevier
Citation
Humphry-Baker, S. A., and C. A. Schuh. "Anomalous grain refinement trends during mechanical milling of Bi2Te3." Acta Materialia 75 (15 August 2014), pp.167-179.
Version
Author's final manuscript
Abstract
The structural evolution of nanocrystalline bismuth telluride (Bi2Te3) during mechanical milling is investigated under different milling energies and temperatures. After prolonged milling, the compound evolves toward a steady-state nanostructure that is found to be unusually strongly dependent on the processing conditions. In contrast to most literature on mechanical milling, in Bi2Te3 we find that the smallest steady-state grain sizes are attained under the lowest energy milling conditions. An analysis based on the balance between refinement and recovery in the steady state shows that two regimes of behavior are expected based on the thermo-physical properties of the milled powder. Bi2Te3 lies in a relatively unusual regime where greater impact energy promotes adiabatic heating and recovery more than it does defect accumulation; hence more intense milling leads to larger steady-state grain sizes. Implications for other materials are discussed with reference to a “milling intensity map” that delineates the set of material properties for which this behavior will be observed.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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Creative Commons Attribution-NonCommercial-NoDerivs License
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DOI of Published Version
https://doi.org/10.1016/j.actamat.2014.04.032