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The site occupancy behavior of tary alloying elements in γ’-Ni3A1 (a key strengthening phase of commercial Nibased single-crystal superalloys) can change with temperature and alloy composition owing to the effect of entropy.Using a total-energy method based on density functional theory,the dependence of tensile and shear behaviors on the site preference of alloying elements in γ’-Ni3A1 were investigated in detail.Our results demonstrate that Fe,Ru,and Ir can significantly improve the ideal tensile and shear strength of the ～ phase when occupying the A1 site,with Ru resulting in the strongest enhancement.In contrast,elements with fully filled d orbitals (i.e.,Cu,Zn,Ag,and Cd) are expected to reduce the ideal tensile and shear strength.The calculated stress-strain relationships of Ni3A1 alloys indicate that none of the alloying elements can simultaneously increase the ideal strength of the γ’phase for both Ni1-site and Ni2-site substitutions.In addition,the charge redistribution and the bond length of the alloying elements and host atoms during the tensile and shear processes are analyzed to unveil the underlying electronic mechanisms.