Grain boundary diffusion of 110mAg in polycrystalline Cu was measured in the type-B (962-675K) or type-C (565-452K) diffusion regimes (tables 34 and 35). In the former regime, the triple-product was found to obey the Arrhenius relationship:

sδD (m3/s) = 1.4 x 10-15 exp[-69.1(kJ/mol)/RT]

Measurements which were performed under C-type conditions showed that the grain-boundary diffusivity was described by:

D (m2/s) = 1.7 x 10-4 exp[-108.6(kJ/mol)/RT]

The data were analyzed in order to determine the factors which affected the curvature of the radiotracer profiles. Non-linear segregation was showed to have only a slight, or zero, effect. The initial portions of the profiles were well-described by taking account of grain boundary motion during diffusion annealing. The analysis showed that hypothetical dislocation-enhanced volume diffusion at low temperatures could not disturb the C-type conditions.

S.Divinski, M.Lohmann, C.Herzig: Acta Materialia, 2001, 49[2], 249–61

Table 34

Grain Boundary Diffusivity of Ag in Cu in the B Kinetics Regime