The microstructural evolution and relaxation strengthening for nano-grained Ni upon low-temperature annealing
The microstructural evolution and relaxation strengthening of nano-grained Ni annealed at a temperature range of 493–553 K were studied by in situ X-ray diffraction technique, transmission electron microscopy, and microhardness evaluation. Upon low-temperature annealing, the rather limited variatio...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2024-12-01
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| Series: | Nano Materials Science |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2589965123000934 |
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| Summary: | The microstructural evolution and relaxation strengthening of nano-grained Ni annealed at a temperature range of 493–553 K were studied by in situ X-ray diffraction technique, transmission electron microscopy, and microhardness evaluation. Upon low-temperature annealing, the rather limited variations of anisotropic grain size and root-mean-square strain, conforming to an exponential relaxation model, yield a consistent activation energy of approximately 0.5 eV, which corresponds to the localized, rapid diffusion of excess vacancies on nonequilibrium surfaces/interfaces and/or defective lattice configurations. Microstructure examinations confirm the grain boundary ordering and excess defect reduction. The relaxation-induced strength enhancement can be attributed to the linear strengthening in the regime of small elastic lattice strains. This study provides an in-depth understanding of low-temperature nanostructural relaxation and its relation to strengthening. |
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| ISSN: | 2589-9651 |