Facilitating the strength-ductility balance in Ni₃Al via Fe co-substitution at two sites

In this work, the effect of Fe substitution on the stability and deformation mechanism of Ni3Al was studied using first principles calculations. The results show that Fe is more likely to occupy the Ni site in terms of energy at low substitution concentrations, but occupying the Al site is more favorable for the stability of the system. The results also show that Fe-Ni substitution brings ductility to the intermetallics while Fe-Al substitution ensures strength. In addition, the results for the generalized stacking fault energies at high substitution concentrations are different from those at low concentrations because of the change in the matrix. Therefore, dual-site substitution of Fe in appropriate proportions can help Ni3Al overcome the strength-ductility trade-off. This work provides useful knowledge for better design and utilization of Ni3Al-based multicomponent intermetallics.