Effects of C impurities on the elastic properties of NiAl intermetallics

The atomic configuration and ductility of NiAl intermetallics affected by C impurity have been studied with a first-principles pseudo-potential method. The calculation results indicate that for the substitutional cases, C prefers to replace Ni other than Al in most of the cases except for the Ni-rich case. As compared with the interstitial cases, the C atom can be more easily occupy the Ni-rich octahedron position in both of the Ni-rich and Al-rich cases. The brittleness will be decreased and the ductility will be increased after the NiAl intermetallics doped with the impurity C atom.