Diffusion in the a-phase, at temperatures of between 823 and 1123K, was measured by means of heavy-ion Rutherford back-scattering spectrometry. A deviation from the Arrhenius law was observed, with 2 different regimes. At low temperatures, the activation energy was close to the expected value for a substitutional diffuser, but the pre-exponential factor was larger than expected. Near to the phase transition temperature, the opposite was true; with a low activation energy.

Lead Diffusion in a-Zr. R.A.Perez, F.Dyment: Applied Physics A, 1999, 68[6], 667-71