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Diffusion In Icosahedral AI-Pd-Mn Quasicrystals
Published online by Cambridge University Press: 10 February 2011
Abstract
In this paper radiotracer diffusion studies from our laboratory on monocrystals of icosahedral quasicrystalline Al-Pd-Mn (i-AlPdMn) are summarized. Diffusion of 65Zn, 54Mn, and 59Fe has been investigated as function of temperature and in the cases of 5 4Mn and 65Zn also as function of hydrostatic pressure. Diffusion of 65Zn was studied to ‘simulate’ Al diffusion. Over a very wide temperature range no deviation from Arrhenius-behaviour is found. Some preliminary results of 114m In diffusion are also reported. The diffusivities in i-AlPdMn reveal parallels to foreign atom diffusion in Al suggesting a vacancy-type mechanism of diffusion for i-AlPdMn. Signs and magnitudes of the activation volumes of +0.67 Ω (Ω = mean atomic volume) for 54Mn and of +0.74 Ω for 65Zn diffusion in Al-Pd-Mn favour a vacancy mechanism as well.
Our results will be discussed together with diffusion studies on i-AlPdMn performed by other groups. The results of Nakajima and coworkers on Mn, Ge, Co and Cr diffusion and the results of Frank and coworkers on Pd and Au diffusion in the high-temperature regime are consistent with the above mentioned conclusion. For the low temperature regime of Pd and Au diffusion the suggested possibility of a phason-related mechanism will be discussed.
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- Copyright © Materials Research Society 1999
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