| Issue |
Matériaux & Techniques
Volume 110, Number 2, 2022
Special Issue on ‘Indentation across scales and techniques: recent advances in experiments and modelling’, edited by Vincent Keryvin
|
|
|---|---|---|
| Article Number | 203 | |
| Number of page(s) | 8 | |
| Section | Métaux et alliages / Metals and alloys | |
| DOI | https://doi.org/10.1051/mattech/2022005 | |
| Published online | 26 April 2022 | |
Regular Article
A combined EBSD/nanoindentation study of dislocation density gradients near grain boundaries in a ferritic steel
1
ArcelorMittal Maizières Research SA, Voie Romaine, BP30320, 57283 Maizières-lès-Metz, France
2
Université de Lorraine, Arts et Métiers Paris Tech, CNRS, LEM3, 57000 Metz, France
* e-mail: layal.chamma@univ-lorraine.fr
Received:
12
November
2021
Accepted:
17
January
2022
Microstructural internal lengths play an important role on the local and macroscopic mechanical behaviors of steels. In this study, the dislocation density gradients near grain boundaries in a ferritic steel are investigated using SEM/EBSD together with instrumented nanoindentation for undeformed and pre-deformed aluminum-killed steels (Al-k) at 3% and 18% tensile plastic strains. The effect of the distance to grain boundaries on Geometrically Necessary Dislocations (GND) densities is first determined by analyzing orientation gradients from 2D-EBSD maps. Then, nanohardness measurements are performed in the vicinity of grain boundaries. Data analyses show a clear correlation between the spatial gradients of GND density and the ones of nanohardness. Using a mechanistic model, the total dislocation densities are estimated from the measured nanohardness values. From both GND and total dislocation density profiles, the value of an internal length, denoted λ, is estimated from the analysis of dislocation density gradients near grain boundaries. At the end, the capabilities of 2D-EBSD and nanoindentation methods to assess this value are discussed.
Key words: dislocation densities / grain boundaries / nanoindentation / EBSD / ferritic steel
© L. Chamma et al., 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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