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Poster Année : 2018

How to in-situ follow the evolution of dislocation configurations during mechanical testing on bulk specimen

Résumé

In the aim of following the fast evolution of the industrial demands, developing innovative techniques that allow to understand and to predict the mechanical properties of materials has become a necessity for the Materials Science community. For instance, mechanical tests followed by microstructural investigations provide engineers with the necessary information to computationally predict the mechanical performance of components. In situ mechanical testing combined with microscopy techniques (SEM and TEM) [1,2,3] is well known for studying the instantaneous evolution of microstructures during exposure to stress. Such experiments allow capturing footprints of the deformation mechanisms responsible for the changing microstructure. For instance, in-situ mechanical testing combined with TEM is generally required for studying the instantaneous evolution of defects during exposure to stress . Today various approaches of mechanical testing inside a TEM exist: TEM holders with a simple mechanical actuation [4], elaborated testing units that fit inside the pole pieces [5,6] or by playing with various coefficients of thermal expansion [1]. Nevertheless, in-situ TEM mechanical testing is experimentally very tough. In addition to the difficult control of the deformation conditions, the space available is generally less than one centimeter and statistics on physical mechanisms is scientifically very weak. Indeed, TEM needs an electron transparent specimen with a thickness of ≈ 100 nm with a useful field of view of few µm². Therefore, fundamental questions on the representativeness of observed phenomenon must be raised when extrapolating discussions to a millimeter-size specimen. In this framework, we have successfully combined mechanical testing of bulk specimen with an in-situ avant-gardist dislocation-scale characterization technic; the accurate Electron Channeling Contrast Imaging (aECCI) [7]. aECCI is a non-destructive groundbreaking procedure offering the ability to provide, inside a SEM, TEM-like diffraction contrast imaging of sub-surface defects (at a depth of about one hundred of nanometers) on centimetric bulk specimen with still unsurpassed resolutions [8,9]. Firstly, technological challenges such as defect contrast comprehension and experiment procedure will be presented. Secondly first in-situ results will be discussed and they clearly show the full potentialities of this groundbreaking and powerful testing set-up. References [1] M. Legros, Comptes Rendus Physique, 2014, 224-240 [2] F.Mompiou, M.Legros, A.Boé, M.Coulombier, J.-P.Raskin,T.Pardoen, Acta Materialia 2013, 205-216 [3] S. Kahla, R. LinPeng, M. Calmunger, B. Olsson, S. Johansson, Micron, 2014, 15-24 [4] F.Mompiou, M. Legros, Scripta Materialia, 2015, 5-8 [5] K. Svensson, Y. Jompol, H. Olin, E. Olsson, Rev. Sci. Instrum., 74, 2003, p. 4945 [6] A. Nafari, F.A. Ghavanini, M. Bring, K. Svensson, P. Enoksson, J. Micromech. Microeng., 17, 2012 [7] H. Kriaa, A. Guitton, N. Maloufi, Scientific reports 7, 2017 [8] H. Mansour, M. A. Crimp, N. Gey, N. Maloufi, Scripta Materialia, 2015, 76-79 [9] A. Guitton, H. Kriaa, E. Bouzy, J. Guyon, N. Maloufi, Materials 11, 2 (2018)
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hal-03165872 , version 1 (11-03-2021)

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  • HAL Id : hal-03165872 , version 1

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Meriem Ben Haj Slama, Hana Kriaa, J Guyon, Nabila Maloufi Maloufi, Jean-Jacques Fundenberger, et al.. How to in-situ follow the evolution of dislocation configurations during mechanical testing on bulk specimen. MRS Fall Meeting & Exhibit, 2018, Boston, United States. . ⟨hal-03165872⟩
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