Effect of segregation on the shape of grain boundary diffusion profiles Experimental study of the Cu[sbnd]Ag system

Grain boundary diffusion of Ag in Cu and in a Cu-0.091 at.% Ag alloy has been investigated. An experimental method to separate the effect of different grain boundaries present in the samples and the effect of segregation on grain boundary diffusion profiles is described. It is shown that in the case of silver diffusion in pure copper the curved penetration plots are due to segregation effects. For pure Cu the obtained activation energy and pre-exponential factor of the triple product P are (90 ± 6.2)kJ mol−1 and (3.7+7.3 −2.5) × 10−14 m3s−1, respectively. For Cu(Ag) alloy these values are (119.4 ± 6.6)kJ mol−1 and (2.1+4.8 −1.5) × 10−12m3s−1, respectively. The activation energy of grain boundary segregation is estimated as 37± 13kJmol−1.