Study of plastically deformed icosahedral Al[sbnd]Pd[sbnd]Mn single quasicrystals by transmission electron microscopy

Abstract

Al[sbnd]Pd[sbnd]Mn single-quasicrystals have been plastically deformed at temperatures between 730 and 800°C up to different strain values and analysed in the transmission electron microscope. Dislocations were created during deformation. The dislocation density ranged between 1·7 × 10⁷ cm⁻² in undeformed samples and 7·8 × 10⁸cm⁻²in material deformed at 732°C. Six-dimensional dislocation Burgers vectors were determined employing the convergent-beam electron diffraction technique. 87% of these Burgers vectors were oriented parallel to twofold directions in three-dimensional physical space. Their moduli were 0·113, 0·183 and 0·296nm. The ratio of the phason to the phonon component of the Burgers vectors was found to increase with increasing strain. A variety of slip systems was observed. In most cases the respective slip plane normals were parallel to fivefold and threefold directions.