Ab-initio approach to the effect of Fe on the diffusion in hcp Zr II: the energy barriers.

R.C. PASIANOT, R. PÉREZ, V.P. RAMUNNI AND M. WAISSMAN

JOURNAL OF NUCLEAR MATERIALS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 392 p. 100 - 104

0022-3115

Using Density Functional Theory calculations together with the Monomer method for the search of saddle points  combined for the first time with an ab initio algo-rithm), we obtain the vacancy formation energies and the migration barriers for hcp-Zr self-diffusion and for the diffusion of interstitial impurities, including the ultra-fast diffuser Fe. Good agreement with measured diffusion coefficients is obtained, as a much lower energy barrier for the ultra-fast diffuser is found. We also suggest a possible mechanism for the increase in self-diffusion due to the Fe impurity, alwayspresent in the experimental samples.