The anomalous flow behavior of γ'-Ni_(3)Al 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.,Γ-surface...The anomalous flow behavior of γ'-Ni_(3)Al 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.,Γ-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 Γ-surfaces and ideal shear strength(τ_(max))in γ'-Ni_(3)Al 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 γ_(APB)^(111)/γ_(APB)^(001) indicates that the anomalous flow behavior of γ'phases at high temperature is not as excellent as the double Re-addition,but an increasedτmax 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 X1_(Al) and X2_(Al) point defects is characterized by an correlation energy function ΔE^(X1_(Al)+X2_(Al))(d),it is found that both strong attraction and strong repulsion are unfavarable for the improvement of yield strengths of γ'phase.展开更多
基金the financial supports from the National Natural Science Foundation of China(Nos.51871096,52071136).
文摘The anomalous flow behavior of γ'-Ni_(3)Al 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.,Γ-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 Γ-surfaces and ideal shear strength(τ_(max))in γ'-Ni_(3)Al 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 γ_(APB)^(111)/γ_(APB)^(001) indicates that the anomalous flow behavior of γ'phases at high temperature is not as excellent as the double Re-addition,but an increasedτmax 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 X1_(Al) and X2_(Al) point defects is characterized by an correlation energy function ΔE^(X1_(Al)+X2_(Al))(d),it is found that both strong attraction and strong repulsion are unfavarable for the improvement of yield strengths of γ'phase.
