Microstructural investigation of the brittle-to-ductile transition in Al-Pd-Mn quasicrystals

Icosahedral Al-Pd-Mn single quasicrystals were deformed between room temperature and 400°C by Vickers hardness testing. The surface morphology was investigated by profiling and scanning electron microscopy. Specimens were prepared for cross-sectional observation in transmission electron microscopes using a focused ion beam system. At room temperature, we find a polygrained microstructure which suggests a deformation via grain-boundary glide. At elevated temperatures, fragmentation as well as dislocation formation are observed.