Diffusion of Pd in alpha-Ti studied by means of Rutherford back-scattering and channelling techniques

摘要

The diffusion of implanted Pd in a-Ti has been studied in the 723-1073 K temperature range by using Rutherford back-scattering and channelling techniques. The measurements show that the diffusion coefficient follows a linear Arrhenius rule D(T) = D-0 exp(-Q/RT), where D-0 =(2.0 +/- 0.5) x 10(-3)m(2)s(-1) and Q = 264 +/- 9 kJ mol(-1). In addition, channelling experiments performed in the 673-973 K temperature interval show that, independent of the annealing temperature, at least 30% of the Pd atoms are at interstitial sites of the Ti matrix. A comparison of the present and previous published data indicates that Pd diffuses more rapidly than substitutional elements but more slowly than the interstitial elements Fe, Co and Mn do. These two features indicate that the diffusion mechanism is not purely substitutional but has a mixed character. [References: 18]