A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding
Abstract Nano-phase separating Ni–12 at. pct Ag powders are processed via high-energy ball milling and brought into a supersaturated state with a reduction of the grain size to the nanocrystalline scale, a combination that is designed to encourage rapid densification by phase separation...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Springer US
2023
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| Online Access: | https://hdl.handle.net/1721.1/152107 |
| _version_ | 1811080594023514112 |
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| author | Naunheim, Yannick Perrin, Alice Oliver, Christian E. Stone, Katherine Schuh, Christopher A. |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Naunheim, Yannick Perrin, Alice Oliver, Christian E. Stone, Katherine Schuh, Christopher A. |
| author_sort | Naunheim, Yannick |
| collection | MIT |
| description | Abstract
Nano-phase separating Ni–12 at. pct Ag powders are processed via high-energy ball milling and brought into a supersaturated state with a reduction of the grain size to the nanocrystalline scale, a combination that is designed to encourage rapid densification by phase separation upon heating. This unstable powder is then characterized by dilatometry, in-situ x-ray diffraction, thermogravimetry and microstructure analysis for sintering cycles up to 940 °C. However, these powder compacts exhibit excessive pore evolution and significant macroscopic swelling caused by removal of the organic process additives. This competition of organic removal with densification is known in nanocrystalline metals, but the present study adds an additional dimension of phase separation, which shifts the dominant swelling mechanism as the formation of the second phase traps the volatilizing organics and hinders the debinding process. The creep swelling and overall loss in relative density is then dominated by the creep deformation of the second Ag phase. The interference between organic removal and low-temperature onset of consolidation represents a new challenge to efforts aimed at rapid free sintering and should guide the design of rapidly sintering alloys; specifically, the present work emphasizes the need to select alloys that have their sintering-accelerating phase separation temperature above the range where gases are evolved. |
| first_indexed | 2024-09-23T11:33:54Z |
| format | Article |
| id | mit-1721.1/152107 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:33:54Z |
| publishDate | 2023 |
| publisher | Springer US |
| record_format | dspace |
| spelling | mit-1721.1/1521072024-01-10T18:32:00Z A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding Naunheim, Yannick Perrin, Alice Oliver, Christian E. Stone, Katherine Schuh, Christopher A. Massachusetts Institute of Technology. Department of Materials Science and Engineering Abstract Nano-phase separating Ni–12 at. pct Ag powders are processed via high-energy ball milling and brought into a supersaturated state with a reduction of the grain size to the nanocrystalline scale, a combination that is designed to encourage rapid densification by phase separation upon heating. This unstable powder is then characterized by dilatometry, in-situ x-ray diffraction, thermogravimetry and microstructure analysis for sintering cycles up to 940 °C. However, these powder compacts exhibit excessive pore evolution and significant macroscopic swelling caused by removal of the organic process additives. This competition of organic removal with densification is known in nanocrystalline metals, but the present study adds an additional dimension of phase separation, which shifts the dominant swelling mechanism as the formation of the second phase traps the volatilizing organics and hinders the debinding process. The creep swelling and overall loss in relative density is then dominated by the creep deformation of the second Ag phase. The interference between organic removal and low-temperature onset of consolidation represents a new challenge to efforts aimed at rapid free sintering and should guide the design of rapidly sintering alloys; specifically, the present work emphasizes the need to select alloys that have their sintering-accelerating phase separation temperature above the range where gases are evolved. 2023-09-13T13:49:26Z 2023-09-13T13:49:26Z 2023-08-10 2023-08-13T03:11:36Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/152107 Naunheim, Yannick, Perrin, Alice, Oliver, Christian E., Stone, Katherine and Schuh, Christopher A. 2023. "A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding." PUBLISHER_CC en https://doi.org/10.1007/s11661-023-07152-3 Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ The Author(s) application/pdf Springer US Springer US |
| spellingShingle | Naunheim, Yannick Perrin, Alice Oliver, Christian E. Stone, Katherine Schuh, Christopher A. A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding |
| title | A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding |
| title_full | A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding |
| title_fullStr | A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding |
| title_full_unstemmed | A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding |
| title_short | A Limit to Accelerated Free-Sintering: Nano-Phase Separation Interferes With Organic Debinding |
| title_sort | limit to accelerated free sintering nano phase separation interferes with organic debinding |
| url | https://hdl.handle.net/1721.1/152107 |
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