Direct evidence of Cottrell atmosphere and Suzuki segregation in Ni-Co-based superalloy deformed at room temperature

The formation of superlattice stacking faults and microtwins in superalloys, especially how partial dislocations penetrate the ordered γ′ phase, remains a fundamental challenge. Although solute segregation and the above planar faults are typically linked to high-temperature creep, we observe Cottrell atmospheres and Suzuki segregation of Co and Cr elements as well as microtwinning in a Ni-Co-based superalloy during room-temperature tensile deformation, enabling a new disordering mechanism in the L12 structure. This chemical reorganization drastically lowered the energy barrier for dislocation cutting into γ′ precipitates, establishing a new framework for plastic deformation in superalloys that transcends conventional thermal activation models.