V. Tölle

On the impurity diffusion in β-Ti

Abstract The impurity-diffusion data in β-Ti are reanalysed on the basis of the assumption that the vacancy-migration enthalpy H 1v M as well as the vacancy-formation enthalpy H 1v F depend on temperature. A simple linear temperature dependence in the form of H(T)=H(T 0 )+αk(T−T 0 ) is used. The results of the analysis show that the impurity-diffusion energy Q 2 increases linearly with α 2 , i.e. Q 2 (T m )≈Q 0 (T m )+8(α 2 −α 0 ) with Q in kJ/mol. Q 0 and α 0 describe the self-diffusion.

Application of the modified electrostatic model to the impurity diffusion in cobalt

The modified electrostatic model (Neumann and Tolle 1995) is applied to the impurity diffusion in nickel.Z0 = 0.4 is used for the effective charge of the nickel ion.

On the diffusion of scandium and hafnium in tungsten

The modified thermodynamic model of impurity diffusion in BCC metals, which is based on the assumption that monovacancy jumps to nearest and next-nearest neighbour positions are responsible for the transport, is applied to the diffusion of Sc and Hf in tungsten. The agreement with experimental data reveals that the applicability of the model is not restricted to impurities of the groups V to VII of the periodic system.