Dislocation drag processes

Experiments showing the influence of electron drag on mobile dislocations a re presented. These show that dislocations overcome barriers sequentially d uring low temperature deformation. Also, the influence of viscosity on rate processes is demonstrated through creep studies of lead alloys in the norm al state and the superconducting state. Finally, experiments are described which provide real time measurements of instantaneous dislocation velocitie s during ordinary tensile deformation. All of these results are tied togeth er through the overriding principle of treating dislocations as underdamped oscillators. (C) 2000 Elsevier Science S.A. All rights reserved.