Abstract
Recent studies of self-diffusion and impurity diffusion in α- and β-titanium are reviewed. The transition metal elements and phosphorus exhibit fast diffusion in α-Ti, which are three to five orders of magnitude faster than the self-diffusion. The mechanism of the fast diffusion is discussed on the basis of the several features: the effect of α→β phase transformation, the diffusion anisotropy, the atomic size effect and the correlation between solubility and diffusivity. In β-Ti self- and impurity diffusion exhibit marked upward curvatures in the Arrhenius plots, which are known as anomalous diffusion, Various models proposed to explain the anomalous behaviour are briefly reviewed.
