First-principles understanding of environmental embrittlement of the Ni/Ni3Al interface

Using first-principles density functional calculations, we determine effects of environmental embrittlement on Ni/Ni3Al interfaces. We evaluate relative stability of sites for occupation of O, H and N and estimate their effects on cleavage energies. We find that O has the most deleterious effect on interface embrittlement, followed by N and H. Changes in bonding near dopant O arising from its strong ionic character, evident in electron localization function, are responsible for the corresponding large reduction in the cleavage energy.