1307.7616 (P. A. Burr et al.)

Hydrogen accommodation in Zr second phase particles: Implications for H
pick-up and hydriding of Zircaloy-2 and Zircaloy-4    [PDF]

P. A. Burr, S. T. Murphy, S. C. Lumley, M. R. Wenman, R. W. Grimes

Ab-initio computer simulations have been used to predict the energies associated with the accommodation of H atoms at interstitial sites in {\alpha}, {\beta}-Zr and Zr.M intermetallics formed with common alloying additions (M = Cr, Fe, Ni). Intermetallics that relate to the Zr2(Ni,Fe) second phase particles (SPPs) found in Zircaloy-2 exhibit favourable solution enthalpies for H. The intermetallic phases that relate to the Zr(Cr,Fe)2 SPPs, found predominantly in Zircaloy-4, do not offer favourable sites for interstitial H. It is proposed that Zr(Cr,Fe)2 particles may act as bridges for the migration of H through the oxide layer, whilst the Zr2(Ni,Fe)-type particles will trap the migrating H until these are dissolved or fully oxidised.

View original: http://arxiv.org/abs/1307.7616