Volume 78, Number 1, April 2007
Article Number 16002
Number of page(s) 4
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 16 March 2007
EPL, 78 (2007) 16002
DOI: 10.1209/0295-5075/78/16002

Non-linear elastic effects in plasticity: $\mth{\{100\}}$ dislocation gliding in aluminum-based alloy

J. Colin1, P. Beauchamp1, S. Brochard1, J. Grilhé1 and A. Coujou2

1  Laboratoire de Métallurgie Physique, UMR 6630 du CNRS, Université de Poitiers - BP 30179, 86962 Futuroscope Cedex, France
2  Centre d'Elaboration des Matériaux et d'Etudes Structurales, CNRS - 29 rue Jeanne Marvig, 31055 Toulouse Cedex, France

received 4 October 2006; accepted in final form 16 February 2007; published April 2007
published online 16 March 2007

In the general framework of non-linear elasticity, a subtle effect of plasticity recently observed in alloys at room temperature, i.e. the gliding instability of dislocations near axi-symmetrical precipitates, has been explained by means of static atomistic simulations. It is demonstrated that the interaction usually neglected between three sources of strain identified as the dislocations, the external applied strain and the precipitates is responsible for the unusual localized cross-slip of the dislocations from the $\{111\}$ to $\{100\}$ planes in zone with the axis of the precipitates. The static atomistic simulations performed at 0 K have clearly shown that the modification of the inter-planar distance in the neighborhood of the precipitates leading to a local modification of the shearing properties is at the origin of this gliding in $\{100\}$ planes recently observed in Al-Mg-Si alloys 6056. It is believed that the third-order interaction emphasized here plays a key role in many other problems such as creep of solids under irradiation for example.

61.72.Lk - Linear defects: dislocations, disclinations.
62.20.Fe - Deformation and plasticity (including yield, ductility, and superplasticity).
61.72.Bb - Theories and models of crystal defects.

© Europhysics Letters Association 2007