Microstructural analysis of plastically deformed icosahedral Zn–Mg–Dy single quasicrystals

Abstract

We present a detailed study of the microstructure of plastically deformed Zn–Mg–Dy single quasicrystals. Single quasicrystals grown using the self-flux technique were uniaxially deformed at strain rates of 10 −5 and 10 −6 s −1 in the temperature range between 490 and 530 °C. Dislocations and planar defects in differently treated samples were analyzed using transmission electron microscopy. Antiphase boundaries (APBs) of the face-centered icosahedral structure were shown to be generated as a result of plastic deformation by moving partial dislocations. The determination of the APB planes, i.e. the planes of dislocation motion, along with an analysis of the Burgers vectors and the line directions of the dislocations attached to the APBs, allowed a detailed microstructural characterization on the mode of plastic deformation. Dislocations of 60° mixed-type were most frequently found. Slip occurs preferentially on planes that are inclined by an angle of almost 45° to the compression direction, i.e. planes of highest resolved shear-stress. It was shown that the mode of dislocation movement is mainly pure glide, though in some cases motion by climb was observed as well.