Abstract text (incl. figure legends and references)

Transmission electron microscopy is the most precise technique to characterize dislocation microstructures. Several techniques are available to determine Burgers vectors be it via extinction contrast, by thickness fringes, or with LACBED. As a linear defect, a dislocation is also determined by its geometry, which gives important information on the deformation mechanisms like glide, climb, or cross-slip. In comparison to Burgers vectors, characterization of line orientations are less common and rely often on the use of the stereographic projection following tilting experiments.

Although applications of tomography in the transmission electron microscope (TEM) date back to the 70s, it is only in 2006 that it has been applied to dislocations [1]. The difficulty lies in the need to cover a large range of tilt while keeping the diffraction contrast rigorously constant. Using electron tomography of dislocations in the TEM provides a quantitative volumetric characterization of the dislocation microstructure. In this presentation, we show how this possibility can be exploited to build an interface with continuum mechanics. This allows in particular to identify the non-zero components of the strain tensor [2] or to determine the Nye tensor of dislocations. A further step is to implement the dislocation microstructure in a Dislocation Dynamics code (DD), NuMoDis [3] to investigate the temporal evolution of the microstructure under stress.

We present applications in quartz and olivine which are important mineral phases of the crust and the mantle respectively. Quartz presents the additional challenge of being very sensitive to electron irradiation which requires an adapted tilted series acquisition strategy.

[1] Barnard, J. S., Sharp, J., Tong, J. R., & Midgley, P. A. (2006). High-resolution three-dimensional imaging of dislocations. Science, 313(5785), 319-319.

[2] Mussi, A., Gallet, J., Castelnau, O., & Cordier, P. (2021). Application of electron tomography of dislocations in beam-sensitive quartz to the determination of strain components. Tectonophysics, 803, 228754.

[3] Drouet, J., Dupuy, L., Onimus, F., Mompiou, F., Perusin, S., Ambard, A. (2014): Dislocation dynamics simulations of interactions between gliding dislocations and radiation induced prismatic loops in zirconium. J. Nucl. Mater., 449, 252-262.