Computational analysis for the microscopic mechanism of corrosion resistance of δ´ and δ precipitates

The quantitative research of the surface properties of δ´ and δ precipitates is critical for exploring the microscopic mechanism of corrosion resistance of Al-Li alloys. Earlier calculation, however, fails to provide the accurate value of surface energy for non-stoichiometric surface of δ´ and δ precipitates. Herein, we employed two different methods to predict the surface energy of non-stoichiometric δ´ (100) surface and δ (100) stoichiometric surface quantitatively. Besides surface energy, the theoretical calculation of work function for δ´ and δ (100) surface is well in agreement with the experimental result. Solute Zr is not only in favor of segregation to δ´/Al interface, but also easily enters into the bulk interior of δ´ precipitate by substituting Li atom, improving the corrosion resistance of Al-Li alloy due to its comparatively high electronegative. (author)