Speaker
Description
Mechanical properties of metallic material can be predicted as a function of their microstructure by constitutive laws [1]. One of the key microstructural parameters, which is often difficult to precisely characterize, is the dislocation density.
For the metallurgical community, there is a need for more representative measurements in order to better describe the mechanical behavior of such materials.
Dislocations can be observed in a SEM using ECCI (Electron Channeling Contrast Imaging), when the sample is correctly oriented in a condition to generate a contrast between the matrix and the dislocations. However, the precise orientation of the sample is difficult due to the SEM set-up.
R-ECCI (Rotational-ECCI) method [2-3], consists in acquiring a series of rotating back scattered electron images. From this image serie, an intensity profile of the different dislocations and of the matrix can be extracted. The dislocation density can then be automatically determined by applying a clustering algorithm on the intensity profiles.
The lowest and highest dislocation density measurable with this method was determined by analyzing a duplex steel sample presenting a deformation gradient. Moreover, a quantitative comparison between the results obtained using this method and traditional measurement techniques such as TEM, XRD and EBSD was achieved.
References:
[1] J. Blaizot et al. / International Journal of Plasticity xxx (2015).
[2] L’hôte, G. et al. Rotational-Electron Channeling Contrast Imaging analysis of dislocation structure in fatigued copper single crystal. Scripta Materialia162, 103–107 (2019).
[3] Cazottes Rotational-Electron Channeling Contrast Imaging analysis of dislocation structure in fatigued copper single crystal. Scripta Materialia162, 103–107 (2019).
Keywords: SEM, R-ECCI, dislocation, deformation, clustering
| Speaker Country | France |
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