The effect of alloying elements on the morphological stability of the interface between γ' (LI2,) and β (B2) phases in the Ni-Al-X system was investigated using the Ni-Al-X ternary diffusion couples annealed at temperatures ranging from 1173 to 1573 K. Planar interfaces were observed in the Ni-Al-X couples with X=Co, Cr, Cu, Fe, Mn, Si and V, while nonplanar interfaces with the Widmanstätten-like structure were formed in the couples with X = Mo, Nb, Ta, Ti and W. The roughness of the unstable interface was found to depend not only on the kind of alloying element, but also on the annealing time and temperature. Such a dependency of interface morphological stability on the alloying element X is related to the thermodynamic properties and the diffusivities of the element AI and the particular alloying element X.
|Number of pages||8|
|Journal||Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing|
|Publication status||Published - 2001 Aug 15|
- Morphological stability
- Phase equilibria