Grain Boundary Diffusion of Fe in High-Purity Copper
Grain boundary (GB) diffusion of 59Fe in high purity polycrystalline copper was measured using the radiotracer technique and precision parallel sectioning in an extended temperature interval. The results of diffusion measurements below 900 K are consistent with Harrison's C kinetics and yield the GB diffusion coefficient of Fe in Cu with the pre-exponential factor of 5.610-6 m2/s and the activation enthalpy of 121 kJ/mol. Unexpectedly strong GB segregation of Fe in Cu hindered reliable determination of the Fe diffusivity in the B kinetics. Additionally, unconventional penetration profiles were measured for GB diffusion of 59Fe in Cu at high temperatures. Molecular dynamics simulation with the literature Finnis-Sinclair type interatomic potentials was performed to shed light into the observed features. A strong effect of the Fe coverage on GB structure and kinetics in pure Cu is predicted at increased temperatures above 900 K.
A. Agüero, J.M. Albella, M.P. Hierro, J. Phillibert and F.J. Pérez Trujillo
J. Ribbe et al., "Grain Boundary Diffusion of Fe in High-Purity Copper", Defect and Diffusion Forum, Vols. 289-292, pp. 211-217, 2009