The behavior of -phase solid solutions exhibited the entire range of characteristics of anomalous diffusion in group-IVb elements. Arrhenius plots of the interdiffusion coefficients (table 117) indicated the operation of a mono-vacancy diffusion mechanism. A temperature dependence of the migration energy resulted from softening of the phonon LA(2/3)<111> mode. A curvature of the Arrhenius plots was attributed to the temperature-dependent T1(1/2)<110> mode. At temperatures of between 1000 and 1900C, the interdiffusion coefficients of these alloys could be assumed to be independent of the composition.

D.Ansel, A.Margottet, M.Boliveau, J.Debuigne: Scripta Materialia, 1996, 34[5], 749-55

 

Table 118

Diffusivity of 95Zr in Hf-18at%Nb

 

Temperature (K)

D (m2/s)

1257

2.38 x 10-15

1319

7.00 x 10-15

1529

1.76 x 10-13

1633

2.40 x 10-13

1981

4.96 x 10-12

2173

1.85 x 10-11