J. Phys. IV France 118 (2004) 27-33
Lattice distortion and basal slip bands in deformed ice crystals revealed by hard X-ray diffractionB. Hamelin1, P. Bastie2, P. Duval3, J. Chevy3 and M. Montagnat3
1 Institut Laue-Langevin, BP. 156X,38042 Grenoble Cedex 9, France
2 Laboratoire de Spectrométrie Physique, CNRS, BP. 87, 38402 St Martin d'Hères Cedex, France
3 Laboratoire de Glaciologie et de Géophysique de l'Environnement, CNRS, BP. 96, 38402 St Martin d'Hères Cedex, France
Hard X-ray diffraction experiments were performed on ice single crystals deformed in pure torsion. The torsion strain appears to be totally accommodated by geometrically necessary basal screw dislocations. Dislocation slip is concentrated on macroscopic basal slip bands, which are clearly seen on the prismatic diffraction lines. The slip band spacing is decreasing with the increase of the finite torsion strain. The deformation appears to result from the increase of the number of slip bands and not from the accumulation of dislocations within these bands. The elastic interaction between dislocations located in neighbouring slip bands is weak since they all have the same sign and move in the same direction.
© EDP Sciences 2004