Abstract
Grain refinement is a widely sought-after feature of many metal production processes and frequently involves a process of recrystallization. Some processing methods use very high strain rates and high strains to refine the grain structure into the nanocrystalline regime. However, grain refinement processes are not clear in these extreme conditions, which are hard to study systematically. Here, we access those extreme conditions of strain and strain rate using single copper microparticle impact events with a laser-induced particle impact tester. Using a combined dictionary-indexing electron backscatter diffraction and scanning transmission electron microscopy approach for postmortem characterization of impact sites, we systematically explore increasing strain levels and observe a recrystallization process that is facilitated by nanotwinning, which we term nanotwinning-assisted dynamic recrystallization. It achieves much finer grain sizes than established modes of recrystallization and therefore provides a pathway to the finest nanocrystalline grain sizes through extreme straining processes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 786-794 |
| Number of pages | 9 |
| Journal | Nature materials |
| Volume | 21 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 2022 |
Funding
This work was primarily supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award no. DE-SC0018091. Support for equipment was also provided through the Office of Naval Research DURIP (grant no. N00014-13-1-0676). A.A.T. thanks the Natural Sciences and Engineering Research Council of Canada Postdoctoral Fellowship for financial support. X.C. and J.M.L. acknowledge the support of the Air Force Office of Scientific Research, under contract no. FA9550-20-0066, for STEM experiments. E.L.P. acknowledges support from the NSF Graduate Research Fellowship Program under grant no. DGE-1745302. FIB and SEM/EBSD were performed at the Harvard University Center for Nanoscale Systems, a member of the National Nanotechnology Coordinated Infrastructure Network, which is supported by the National Science Foundation under NSF award no. ECCS-2025158. We thank Y. Sun for assistance in conducting the LIPIT experiment.
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- General Materials Science