Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy
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 stag...
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| Format: | Article |
| Language: | English |
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American Physical Society
2018
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| Online Access: | http://hdl.handle.net/1721.1/118391 https://orcid.org/0000-0003-3433-0078 https://orcid.org/0000-0001-9856-2682 |
| _version_ | 1826191086578565120 |
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| author | Amram, Dor Schuh, Christopher A |
| author2 | Massachusetts Institute of Technology. Center for Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Center for Materials Science and Engineering Amram, Dor Schuh, Christopher A |
| author_sort | Amram, Dor |
| collection | MIT |
| description | 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. |
| first_indexed | 2024-09-23T08:50:19Z |
| format | Article |
| id | mit-1721.1/118391 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:50:19Z |
| publishDate | 2018 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/1183912022-09-30T11:37:03Z Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy Amram, Dor Schuh, Christopher A Massachusetts Institute of Technology. Center for Materials Science and Engineering Massachusetts Institute of Technology. Department of Materials Science and Engineering Amram, Dor Schuh, Christopher A 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. United States. Army Research Office (Grant W911NF-14-1-0539) National Science Foundation (U.S.) (Grant DMR1606914) European Commission. (Marie Skłodowska Curie Global Fellowship Grant 740384) 2018-10-09T17:07:12Z 2018-10-09T17:07:12Z 2018-10 2018-08 2018-10-01T18:00:15Z Article http://purl.org/eprint/type/JournalArticle 0031-9007 1079-7114 http://hdl.handle.net/1721.1/118391 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 https://orcid.org/0000-0003-3433-0078 https://orcid.org/0000-0001-9856-2682 en http://dx.doi.org/10.1103/PhysRevLett.121.145503 Physical Review Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Physical Society application/pdf American Physical Society American Physical Society |
| spellingShingle | Amram, Dor Schuh, Christopher A Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy |
| title | Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy |
| title_full | Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy |
| title_fullStr | Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy |
| title_full_unstemmed | Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy |
| title_short | Higher Temperatures Yield Smaller Grains in a Thermally Stable Phase-Transforming Nanocrystalline Alloy |
| title_sort | higher temperatures yield smaller grains in a thermally stable phase transforming nanocrystalline alloy |
| url | http://hdl.handle.net/1721.1/118391 https://orcid.org/0000-0003-3433-0078 https://orcid.org/0000-0001-9856-2682 |
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