First-principles study of NiAl microalloyed with Sc, Y, La and Nd

The structural, elastic, and electronic properties of NiAl microalloyed with rare earth elements (REEs) Sc, Y, La and Nd are investigated by using Density Functional Theory (DFT). It is found that Sc and La tend to substitute for Al site, while Y and Nd tend to substitute for Ni site, and Nd causes the largest lattice distortion. The elastic constants show that Sc, Y, La and Nd improve the ductility of NiAl. Ni8Al7La is more ductile and Ni8Al7Sc is harder, which could be explained by the increase of ionicity between Ni and Al in Ni8Al7La. The results agree well with the available experimental data and other theoretical results.

Research highlights
► Sc and La tend to substitute for Al site, while Y and Nd tend to substitute for Ni site.
► Sc, Y, La and Nd improve the ductility of NiAl.
► Ni8Al7La is more ductile and Ni8Al7Sc is harder.
► The ionicity between Ni and Al in Ni8Al7La is increased.