The tracer diffusion of 44Ti in single crystals at 1133 to 1307K was studied by means of ion-beam sputter sectioning. The diffusivities were measured parallel to, and perpendicular to, the [001] axis. The data could be described by:

44Ti[001]:     D (m2/s) = 7.66 x 10-4 exp[-3.22(eV)/kT]

44Ti||[001]:     D (m2/s) = 2.38 x 10-7 exp[-3.85(eV)/kT]

It was found that the diffusivity of 44Ti in the direction perpendicular to [001] was about an order of magnitude higher than that parallel to [001]. This anisotropy was attributed to the defect structure and the correlation factor.

T.Ikeda, H.Kadowaki, H.Nakajima: Acta Materialia, 2001, 49[17], 3475-85