The anomalous flow behavior of γ'-Ni3Al phases at high temperature is closely related to the cross-slip of 1/2〈110〉{111} super-partial dislocations. Generalized stacking fault energy curves (i.e., Г-surfaces) along the lowest energy path can provide a great deal of information on the nucleation and movement of dislocations. With the first-principles calculation, the interplay between Re and W, Mo, Ta, Ti doped at preferential sites and their synergetic influence on Г-surfaces and ideal shear strength (τmax) in γ'-Ni3Al phases are investigated. Similar to single Re-addition, the Suzuki segregation of W at stacking faults is demonstrated to enable to impede the movement of 1/6〈112〉{111} Shockley partial dislocations and promote the cross-slip of 1/2〈110〉{111} super-partial dislocations. With the replacement of a part of Re by W, a decreased γ1A1P1001B APB/γ indicates that the anomalous flow behavior of γ' phases at high temperature is not as excellent as the double Re-addition, but an increased τmax means that the creep rupture strength of Ni-based single crystal superalloys can be benefited from this replacement to some extent, especially in the co-segregation of Re and W at Al-Al sites. As the interaction between X1Al and X2Al point defects is characterized by an correlation energy function ΔEX1Al+X2Al(d ) , it is found that both strong attraction and strong repulsion are unfavarable for the improvement of yield strengths of γ' phase.
Ni-based single crystal superalloyγ'-Ni3Algeneralized stacking fault energyideal shear strengthdislocationcross-slip
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