Solute diffusion of Pd and Ir in aluminium

Diffusion of 103Pd and 192Ir in aluminium single crystals has been studied as a function of temperature using the radiotracer sectioning technique. Oxide hold-up effects due to the oxide layer on Al and solubility problems were avoided in the present work. These can lead to complicated diffusion profiles and erroneous diffusion results. Pd diffuses significantly slower than Al with a high activation enthalpy and a high pre-exponential factor. The heavy transition metal Ir diffuses slightly faster than Al self-diffusion and its activation parameters are quite normal. The results are compared with literature work on solute diffusion in Al and discussed in terms of vacancy-solute interactions. The Pd data are also compared to available data on Pd diffusion in icosahedral AlPdMn quasicrystals. (orig.)