First principles investigation on the stability and elastic properties of Ni2Cr1−xMx (M = Nb, Mo, Ta, and W) superlattices

Ni2Cr-type superlattices widely exist in Ni–Cr based and Ni–Mo based alloys. This work focus on the alloying behavior of M (M = Nb, Mo, Ta, and W) in Ni2Cr1−xMx superlattices and their electronic structures by first principles calculations based on the density functional theory. The energetic stability and elastic properties are studied by calculating the formation energy, cohesive energy, and independent elastic constants. The results reveal that all the studied alloying elements could not only improve the thermal stability of Ni2Cr superlattice but also modify its elastic anisotropy within the studied alloying range (that is, x ≤ 0.15).

► Ab-initio calculations for Ni2Cr1−xMx (M = Nb, Mo, Ta, and W) superlattices have been performed. ► Geometry optimization, electronic, stability and elastic properties are investigated. ► The bonding characteristics of Ni2Cr1−xMx (M = Nb, Mo, Ta, and W) superlattices show strong covalent nature up to x = 0.25. ► The alloying elements M (M = Nb, Mo, Ta, and W) not only effectively improve the thermal stability of Ni2Cr superlattice but also modify its elastic anisotropy.