Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy
Name
PhysRevLett.121.145503.pdf
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1.18 MB
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Adobe PDF
Checksum (MD5)
1752f563873f4ffc3ac9ba0316894ab0
Author(s)
Amram, Dor
Schuh, Christopher A
Date Issued
October 2018
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Amram, Dor, and Christopher A. Schuh. “Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy.” Physical Review Letters, vol. 121, no. 14, Oct. 2018. © 2018 American Physical Society
Version
Final published version
Abstract
Grains in crystalline materials usually grow with increased thermal exposure. Classical phenomena such as recrystallization may lead to a purely temporary decrease in the grain size, while recent advances in alloy design can yield thermally stable nanocrystalline materials in which grain growth stagnates. But grains never shrink, since there is a lack of interface-generating mechanisms at high temperatures, which are required to decrease the grain size if such was the system’s thermodynamic tendency. Here we sidestep this paradigm by designing a nanocrystalline alloy having an allotropic phase transformation—an interface-generating mechanism—such that only the high-temperature phase is stabilized against grain growth. We demonstrate that for an Fe-Au alloy cycled through the α↔γ transformation, the high-temperature phase (γ-Fe) has a stable fine grain size, smaller than its low-temperature counterpart (α-Fe). The result is an unusual material in which an increase in temperature leads to finer grains that are stable in size.
MIT Department
Massachusetts Institute of Technology. Center for Materials Science and Engineering
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.121.145503
