Plasticity of icosahedral Zn-Mg-Dy single quasicrystals

We present the results of first deformation experiments on Zn-Mg-Dy icosahedral single quasicrystals. The samples were produced by the flux growth technique. The plastic deformation experiments were performed at temperatures between 490 and 530 degreesC at strain rates of 10(-5) and 10(-6) s(-1). The thermodynamic activation parameters of the deformation process were determined. The stress-strain curves show strong yielding followed by a steady state regime with a constant flow stress level up to strains of about 8%. Microstructural investigations by transmission electron microscopy on deformed samples indicate a deformation mechanism mediated by dislocations. We found a high density of planar defects which were interpreted as slip planes of moving dislocations. (C) 2000 Elsevier Science B.V. All rights reserved.