Microscopic insights into the mechanical behavior of a Ni-Co-based superalloy through neutron diffraction

Liu, Y.*; Yan, Z.*; Gao, Y.*; Li, Y.*; Gan, B.*; Harjo, S.   ; Gong, W.   ; 川崎 卓郎   ; Li, S.*; Wang, Y.-D.*

Liu, Y.*; Yan, Z.*; Gao, Y.*; Li, Y.*; Gan, B.*; Harjo, S.; Gong, W.; Kawasaki, Takuro; Li, S.*; Wang, Y.-D.*

The micromechanical behaviors and dislocation evolution in a polycrystalline Ni-Co-based superalloy were systematically investigated by neutron diffraction tensile testing combined with line profile analysis. The results reveal the sequential activation of ' shearing and Orowan looping mechanisms, with interphase load partitioning governed by strain-dependent interactions of dislocation and precipitate. During the initial plastic deformation, the and ' phases undergo co-deformation through dislocation shearing without load transfer, while the Orowan looping facilitates the load transfer from to ' phase at a higher strain level. Furthermore, the low stacking fault energy leads to a rising fraction of screw dislocations by suppressing cross-slip. Crucially, the pinning effect of ' precipitates hinders the rearrangement of these dislocations into low-energy structures, resulting in the formation of high-energy, weakly screened dislocation configurations. These findings provide new evidence for the planar slip dominance in Ni-Co-based superalloys, enabling quantitative assessment of microstructural evolution and micromechanical responses.