Diffusion in icosahedral Al-Pd-Mn quasicrystals: temperature and pressure dependence

The temperature and pressure dependence of diffusion in monocrystalline icosahedral Al-Pd-Mn quasicrystals (i-Al-Pd-Mn) was investigated by radiotracer techniques using serial sectioning for depth profiling. Recent results on the temperature dependence of Zn-65, In-114m and Pd-103 diffusion are presented together with previous ones on Mn-54 and Fe-59 diffusion from our laboratory. The temperature dependence of diffusion is discussed in connection with results on i-Al-Pd-Mn from other groups and compared with the diffusion of foreign elements in Al. This comparison suggests a vacancy mechanism for diffusion in i-Al-Pd-Mn at least at higher temperatures. Magnitude and sign of the activation volumes also support a vacancy mechanism. (C) 2000 Elsevier Science B.V. All rights reserved.