This diffusion couple interface was examined by means of analytical electron microscopy and high-resolution electron microscopy. It was shown that the Ni-rich solid solution () phase transformed from the Ni3Al-based intermetallic () phase and extended into the  phase during diffusion annealing. The orientations of the  and  phases remained the same. Coherency existed across the / phase boundary. The position of the boundary was not well-defined, but it was in an equilibrium condition in terms of composition.

M.Watanabe, Z.Horita, D.J.Smith, M.R.McCartney, T.Sano, M.Nemoto: Acta Metallurgica et Materialia, 1994, 42[10], 3381-7