The diffusivity of 44Ti in β-phase material was studied by using radio-tracer and serial sectioning methods. The Arrhenius plot exhibited a marked upward curvature. This anomalous behavior was related to an experimentally observed softening of the (2/3)[111] phonon mode, and was explained in terms of a monovacancy mechanism with a temperature-dependent migration enthalpy. The diffusion behavior at 1176 to 1893K could be described by:

D (cm2/s) = 3.5 x 100 exp[-3.4(eV)/kT]

U.Köhler, C.Herzig: Physica Status Solidi B, 1987, 144[1], 243-51

The best linear fits to the solute diffusion data ([1204] to [1206], [1226] to [1227], [1234] to [1237]) yield:

Al: Ln[Do] = 0.46E – 31.1 (R2 = 0.998); O: Ln[Do] = 0.28E – 11.8 (R2 = 0.77);

Ti: Ln[Do] = 0.25E – 17.1 (R2 = 0.85)