Dislocation arrangement and density in deformed Al-Pd-Mn single-quasicrystals

We present results of microstructural investigations on plastically deforme d Al-Pd-Mn single-quasicrystals. Deformations were carried out in uniaxial geometry at different temperatures and to different values of plastic strai n and in bending geometry. In the uniaxial geometry, various glide systems are activated. The dependence of the total dislocation density on temperatu re and on plastic strain is studied. Additional heat treatments on deformed samples show that recovery processes occurring at the high deformation tem peratures significantly influence the deformation process. The experimental data are interpreted using a kinetic equation describing the evolution of the dislocation density during deformation. In the bending geometry a defin ed arrangement of geometrically necessary dislocations of edge type is obse rved. We find straight dislocation lines with line directions in the plane spanned by the direction of the applied force and the bending axis. The Bur gers vectors have twofold direction corresponding to glide planes with the highest shear stress. (C) 2000 Elsevier Science B.V. All rights reserved.