The coarsening of spherical γ-Fe and α-Fe precipitate particles in Cu-Fe alloys aged at 600, 650 and 700C was studied by measuring the particle size using transmission electron microscopy, and the Fe concentration in the Cu matrix via resistometry. The average size of the γ-Fe and α-Fe particles increased with aging time, as t1/3; as predicted by the Lifshitz-Slyozov-Wagner theory. The kinetics of depletion of supersaturation with time for the γ-Fe and α-Fe particles were consistent with the predicted t-1/3 time law. The solubilities of Fe in equilibrium with a γ-Fe particle of infinite size were greater than those in equilibrium with an α-Fe particle of infinite size. The Fe/Cu interface energy, and the diffusivity of Fe in Cu, were deduced independently; from coarsening data. The coherent γ-Fe/Cu interface energy was estimated to be 0.25J/m2, and the incoherent α-Fe/Cu interface energy was 0.52J/m2. The diffusivity of Fe in Cu could be described by:

D (m2/s) = 9.75 x 10-5 exp[-213(kJ/mol)/RT]

R.Monzen, K.Kita: Philosophical Magazine Letters, 2002, 82[7], 373-82