Effect of free surfaces on dislocation configurations: experiment and modeling
| Autor: | Kriaa, Hana, TAUPIN, Vincent, Guitton, Antoine, Capolungo, Laurent, MALOUFI, NABILA |
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| Přispěvatelé: | Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), Labex DAMAS, Université de Lorraine (UL), Georgia Tech - CNRS [Metz] (UMI2958), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec-Georgia Institute of Technology [Lorraine, France]-Georgia Institute of Technology [Atlanta]-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Nationale Supérieure des Arts et Metiers Metz, Los Alamos National Laboratory (LANL) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | TMS2021 Annual Meeting & Exhibition TMS2021 Annual Meeting & Exhibition, Mar 2021, Virtual, United States |
| Popis: | International audience; In plasticity deformation mechanisms are controlled by dislocations. A considerable progress of research over time allowed the development of different techniques to observe and characterize experimentally and/or numerically these linear defect. For example, the Transmission Electron Microscopy (TEM) was the most used technique that allowed experimental evidences and studies of the dislocation role in deformation mechanisms [1]. Accurate Electron Channeling Contrast Imaging (A-ECCI) is a non-destructive procedure that provides, also, TEM-like diffraction contrast imaging of defects in bulk specimens and moreover their full characterization [2,3,4]. For both techniques, the presence of a free surface (two surfaces for a TEM thin foil of about ≈100 nm thick and one surface for bulk specimen characterized by A-ECCI) can affect the nearby dislocation configurations. Furthermore, in case of A-ECCI, the electron channeling intensity signal acquired comes from the top layer of a thickness of ≈ 150 nm in the material. Therefore, an in-depth approach for understanding the influence of free surface on dislocation configurations is required. In order to address this crucial scientific challenge, we proposed to combine fundamental experience both in experiments and modeling. For the experimental part, several micro-volumes of different thickness, prepared by Focus Ion Beam (FIB), are characterized to be able to study the effect of the free surface on the dislocation configurations. Numerically, microstructures similar to the experimentally characterized micro-volumes is simulated by Discrete Dislocation Dynamics (DDD). In our approach, the microstructures are self-relaxed in the presence of numerically added free surfaces to simulate the progressive thinning of the sample [5,6]. The resulting structures in a thin layer close to the surface will be analyzed and compared to the experimental observations. The model results are expected to better understand the effect of surfaces on the redistribution of internal stress and then on the dislocation dynamics, and further to explore how dislocation structures near the surface, and the only ones accessible by these techniques (A-ECCI and TEM), can be different from those in the bulk, which have a considerable effect on the macroscopic behavior.Key words: dislocations, free surface, A-ECCI, TEM, micro-volume, FIB, DDD.References [1] J. W. Edington. Interpretation of Transmission Electron Micrographs. London, 1976[2] H. Mansour, M. A. Crimp, N. Gey, N. Maloufi. Scripta Materialia, 76-79, 2015[3] H. Mansour, J. Guyon, M. Crimp, N. Gey, B. Beausir and N. Maloufi. Scr. Mater., Vols. 84-85,11-14,2014[4] H. Kriaa, A Guitton, N. Maloufi. Scientific reports 7, 2017[5] K.S. Djaka, A. Villani, V. Taupin, L. Capolungo, S. Berbenni. Computer Methods in Applied Mechanics and Engineering 315, 921-942 (2017)[6] L. Capolungo, V. Taupin. Materials Theory 3, 2 (2019)[7] D. Hull and D.J. Bacon, Introduction to Dislocations, Butterworth-Heinemann, Oxford (2001). |
| Databáze: | OpenAIRE |
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