importance for understanding mechanisms of grain boundary (GB) oxidation causing environmental degradation and cracking of Ni-base structural alloys. In this study, first-principles calculations of vacancy-mediated diffusion are performed across a wide series of alloying elements commonly used in Ni-based superalloys, as well as interstitial diffusion of atomic oxygen and sulfur in the bulk, at the (111) surface, symmetric tilt GBs of Ni corresponding to model low- (S=3/(111)) and high-energy (S=9/(221)) GBs. A substantial enhancement of diffusion is found for all species at the high-energy GB as compared to the bulk and the low-energy GB, with Cr, Mn and Ti exhibiting remarkably small activation barriers (
Revised: July 29, 2015 |
Published: April 14, 2015
Citation
Alexandrov V.Y., M.L. Sushko, D.K. Schreiber, S.M. Bruemmer, and K.M. Rosso. 2015.Ab Initio Modeling of Bulk and Intragranular Diffusion in Ni Alloys.The Journal of Physical Chemistry Letters 6, no. 9:1618-1623.PNNL-SA-110894.doi:10.1021/acs.jpclett.5b00177