Ab Initio Study Of Site Preference And Partition Of Alloying Elements In Co-based Superalloys

The site preference of alloying elements inγ-Co₃(Al, W), and the partitioning be-haviors of Re and Ru betweenγandγphases in Co-based superalloys are investigatedby ab initio calculations.The site preference of various alloying elements in Co₃(Al, W) are studied usingfirst principle VASP method. The elements include Mo,Ta,platinum group metals(Ru,Rh,Pd,Os,Ir and Pt) and 3d metal elements (Ni,Fe,Mn,Cr,V and Ti). Theresult we present in current work based on a proper model of 32-atomγ-Co₃(Al, W)supercell, which is confirmed to be valid for the study of site preference of alloyingelements.The calculation results of site preference of alloying elements inγ-Co₃(Al, W)are as follows. For Mo,Ta and platinum group metals (PGMs), Mo, Ta, Rh, Ir andPt can stabilizeγphase. The addition of those PGMs element modifies the latticeparameter ofγphase and it increases in the order of Mo< Ta < Rh < Ru < Os < Ir 3(Al, W), respectively. Moreover, the investigation of the impurity-induced chargedensity characteristics shows that the strong interaction between Re(Ru) and its NNCo atoms inγphase conduce to theγ-phase partitions of Re and Ru, and the stronginteractions between Re-Ru-W inγphase are responsible for the in?uence e?ect ofRu addition on the partitioning behavior of Re.