The Effect of Alloying Element M (M = Fe, Nb, Mo, Hf, and Ta) on the Stability and Elastic Properties of Ni2(Cr,W) Superlattice: A First Principles Investigation

Ni2(Cr,W) superlattice is a newly found age-hardened phase in Haynes 230 alloy, which has great influence on the creep performance of the alloy. We have employed first-principals method based on density functional theory to elucidate the effect of multi-alloying on the stability and elastic properties of Ni2(Cr,W) superlattice. We find that Ni2Cr _1--2x WxMx (M = Fe, Nb, Mo, Hf, and Ta) superlattices are more energetically stable relative to Ni2(Cr,W) superlattice, indicating that the studied alloying elements may improve the stability of Ni2(Cr,W) superlattice to different extent, except for Fe based on DOS analysis. According to the elastic properties investigation, it is revealed that W + M (M = Nb, Mo, and Ta) co-alloying could improve the ductility tendency of Ni2(Cr,W) superlattice. Mo and Nb are relatively effective alloying elements for the Ni2(Cr,W) superlattice in terms of formation enthalpy and ductility in the studied elements.