Quantitative investigation of grain boundary sliding in halite rock by SEM in situ testing and full field strains measurements

Ababacar Gaye (1) , Mathieu Bourcier (2) , Eva Heripre (2) , Michel Bornert (1) , Alexandre Dimanov (2) , Jean Raphanel (2) , Karam Sab (1)

1 navier umr 8205 - Laboratoire Navier
2 LMS - Laboratoire de mécanique des solides

An experimental investigation of the deformation mechanisms acting in halite at the scale of its polycrystalline microstructure is presented. Uniaxial compression tests on centimetric samples are performed inside the chamber of a scanning electron microscope and the obtained high definition images are processed by digital image correlation (DIC) routines. A special marking procedure provides an appropriate contrast at microscale. Standard DIC routines qualitatively demonstrate the coexistence of two deformation mechanisms: crystal slip plasticity and grain boundary sliding. A specific post-processing of the DIC-evaluated displacement fields provides a first quantification of the relative contribution of these mechanisms to overall strain and a dependence with grain size can be demonstrated. A modified DIC formulation able to separate intra-grain deformation from interfacial gliding is also proposed for a better quantification and preliminary results are presented. Such data will be of primary interest for the construction of physically-based multiscale models of the mechanical properties of halite, which might be used for security assessment of deep caverns in salt-rock.

Mots clés: GRAIN; ROCHE; MICROSTRUCTURE; COMPORTEMENT MECANIQUE

Domaines: Sciences de l'ingénieur [physics]

Ababacar Gaye, Mathieu Bourcier, Eva Heripre, Michel Bornert, Alexandre Dimanov, et al.. Quantitative investigation of grain boundary sliding in halite rock by SEM in situ testing and full field strains measurements. Photomechanics 2013, May 2013, Montpellier, France. 5 p. ⟨hal-01587092⟩