Grain growth phenomenon during pressure-induced phase transformations at room temperature
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arXiv
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| Main Authors: | , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866913390737227776 |
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| author | Levitas, Valery I. Pratoori, Raghunandan Popov, Dmitry Park, Changyong Velisavljevic, Nenad |
| author_facet | Levitas, Valery I. Pratoori, Raghunandan Popov, Dmitry Park, Changyong Velisavljevic, Nenad |
| contents | Significant grain growth is observed during the high-pressure phase transformations (PTs) at room temperature within an hour for various materials. However, no existing theory explains this phenomenon since nanocrystals do not grow at room temperature even over a time span of several years because of slow diffusion. Here, we suggest a multistep mechanism for the grain growth during $α\rightarrowω$ PT in Zr. Phase interfaces and grain boundaries (GBs) coincide and move together under the action of a combined thermodynamic driving forces. Several intermediate steps for such motion are suggested and justified kinetically. Nonhydrostatic stresses due to volume reduction in the growing $ω$ grain promote continuous growth of the existing $ω$ grain instead of a new nucleation at other GBs. In situ synchrotron Laue diffraction experiments confirm the main predictions of the theory. The suggested mechanism provides a new insight into synergistic interaction between PTs and microstructure evolution. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2406_09461 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Grain growth phenomenon during pressure-induced phase transformations at room temperature Levitas, Valery I. Pratoori, Raghunandan Popov, Dmitry Park, Changyong Velisavljevic, Nenad Materials Science Significant grain growth is observed during the high-pressure phase transformations (PTs) at room temperature within an hour for various materials. However, no existing theory explains this phenomenon since nanocrystals do not grow at room temperature even over a time span of several years because of slow diffusion. Here, we suggest a multistep mechanism for the grain growth during $α\rightarrowω$ PT in Zr. Phase interfaces and grain boundaries (GBs) coincide and move together under the action of a combined thermodynamic driving forces. Several intermediate steps for such motion are suggested and justified kinetically. Nonhydrostatic stresses due to volume reduction in the growing $ω$ grain promote continuous growth of the existing $ω$ grain instead of a new nucleation at other GBs. In situ synchrotron Laue diffraction experiments confirm the main predictions of the theory. The suggested mechanism provides a new insight into synergistic interaction between PTs and microstructure evolution. |
| title | Grain growth phenomenon during pressure-induced phase transformations at room temperature |
| topic | Materials Science |
| url | https://arxiv.org/abs/2406.09461 |