Microprocesses of the plastic deformation of icosahedral Al-Pd-Mn single quasicrystals

Recent experimental observations on the plastic deformation of icosahedral Al-Pd-Mn single quasicrystals are described originating from conventional t ransmission electron microscopy in a high-voltage electron microscope (HVEM ), from in situ straining experiments in an HVEM and from the determination of activation parameters from macroscopic compression tests at low tempera tures. The moving dislocations are created by multiplication events initiat ed by cross slip. They trail planar faults of different electron microscopy contrast. Since recovery occurs at high temperatures, the dislocation mobi lity should be discussed on the basis of low-temperature data. While it was previously interpreted in terms of an extended cluster friction model, the present paper shows that it can equivalently be explained by the Peierls m echanism on the cluster scale. (C) 2000 Elsevier Science B.V. All rights re served.