The electronic properties of a Σ = 9 tilt grain boundary, with segregated Na and Ca impurity atoms, were calculated by using a first-principles pseudopotential method. The results showed that the boundary expanded, and the charge density decreased significantly over the whole boundary, due to the segregation of Na and Ca. There were no stronger bonds than those which were associated with metallic bonding in the boundary; not even with the impurities. It was concluded that embrittlement promotion by Na or Ca segregation involved a form of decohesion.

Ab initio Pseudopotential Studies of an Al Σ = 9 Grain Boundary - Effects of Na and Ca Impurities. G.H.Lu, A.Suzuki, A.Ito, M.Kohyama, R.Yamamoto: Philosophical Magazine Letters, 2001, 81[11], 757-66