UNCONVENTIONAL PROPERTIES OF DISLOCATIONS IN QUASI-CRYSTALS

Dislocations in quasicrystals are defined as the intersections of disl ocations in a high dimensional lattice with an irrational cut which fi gures the physical space. This definition confers to them a number of unusual geometrical properties which can be studied either by suitable extensions of the Volterra process, or by topological approaches, whi ch often offer complementary points of view and are presented in this paper. Amongst these unusual properties, the production of stacking fa ults under shear at low temperature, reshuffling processes on stacking faults, and properties of non-commutativity which could have some inc idences on the interplay between dislocations in deformation processes are mentioned.