Intrinsic heterogeneity of grain boundary states in ultrafine-grained Ni: A cross-scale study by SIMS and radiotracer analyses

Belkacemi, L.T. and Vaidya, M. and Sevlikar, S. and et al, . (2022) Intrinsic heterogeneity of grain boundary states in ultrafine-grained Ni: A cross-scale study by SIMS and radiotracer analyses. Materialia, 22. pp. 1-12. ISSN 2589-1529

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Abstract

Using a correlated diffusion study applying secondary-ion mass spectroscopy (SIMS) and radiotracer analyses, the co-existence of both relaxed and deformation-modified non-relaxed high-angle grain boundaries (GBs) in ultrafine-grained Ni of 2N6 purity processed by equal channel angular pressing (ECAP) is clearly revealed. Due to different depth and lateral resolutions and using experimentally accessible diffusion times, SIMS provides a direct access to the properties of relaxed “slow” GBs (at short penetration depths) while the radiotracer measurements reveal simultaneously the contribution of the deformation-modified “fast” GBs (at large penetration depths). The temperature stability of ultrafine-grained structure of 2N6 Ni is investigated using electron back-scatter diffraction after annealing treatments corresponding to the diffusion experiments. No changes of the ECAP-produced microstructure occur at 403 K, while the ultrafine-grained structure is remarkably evolving to a coarse-grained one at 603 K. The knowledge of the microstructure evolution is used to quantify the diffusion data. The combination of the two complementary techniques allows not only to perform a cross-scale analysis of the mass transport, but also to probe consistently the existence and kinetic properties of different multi-level hierarchic microstructure features. Therefore, the results obtained is a step forward a better understanding of the physics of ultra-fine-grained materials (UFG). For the first time in the case of UFG materials, the SIMS technique is used in a mode with lateral resolution which is correlated with the microstructure characteristics resolving a multi-level hierarchy of diffusion properties of short circuits in severe plastically deformed materials. © 2022 Acta Materialia Inc.

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IITH Creators:

IITH Creators	ORCiD
Vaidya, M.	https://orcid.org/0000-0001-7866-7348

Item Type:

Article

Additional Information:

The authors are grateful to Prof. Y. Estrin and Dr. R. Lapovok (Monash University, Clayton, Australia) for fruitful collaboration and support in ECAP experiments. The funding by the French-German ANR-DFG DIPLOX project ( DI 1419/16–1 and ANR-17-CE08–0049 ) is gratefully acknowledged.

Uncontrolled Keywords:

Diffusion; EBSD; Geometrically necessary dislocations; Grain boundaries; Ultrafine-grained materials

Subjects:

Physics
Materials Engineering > Materials engineering

Divisions:

Department of Material Science Engineering

Depositing User:

. LibTrainee 2021

Date Deposited:

28 Jun 2022 08:52

Last Modified:

29 Jun 2022 10:29