Diffusion in Icosahedral Zn-Mg-RE and AI-Pd-Mn Quasicrystals

摘要

Single crystals of icosahedral Zn-Mg-RE (RE = rare earth element) quasicrystals were grown by the top seeded solution growth method in the laboratory at Frankfurt. Diffusion of~(65)Zn was studied in icosahedral quasicrystalline alloys of Zn-Mg-Ho and Zn-Mg-Y employing the radiotracer serial sectioning method in Muenster. Diffusion is described by an Arrhenius equation in the whole temperature range investigated. The activation enthalpy of 150 kJ mol~(-1) and the pre-exponential factor of 2.86 @10~(―4) m~2s~(―1) are both typical for a vacancy-mediated diffusion process. We compare the present results with self-diffusion in Zn and with published results for diffusion in icosahedral Al-Pd-Mn from our laboratory at Muenster and with literature data from other groups. The present experiments provide for the first time diffusion data for the majority component (Zn) of a quasicrystal.