Unveiling the Re effect on compression behavior and stacking faults of γ′-phase in Ni-based single crystal superalloys

In response to the increased demand for service reliability of industrial gas turbine (IGT) blades, the compression deformation behavior of three Ni-based single crystal superalloys with different Re additions (0Re, 1.5Re and 3Re, in wt%) from room temperature to 980 °C was studied. The microstructure evolution of alloys was analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the strength at low temperature (≤760 °C) of the three alloys has little difference, but the strength at high temperature increases with the increase of Re content. Further microstructure characterization shows that the distribution of Re elements in γ-phase promotes the formation of uniform and dense interfacial dislocation network, and at the same time prevents the dislocations from cutting γ′-phase and inhibits the formation of SFs (stacking faults). In addition, the segregation of Re at SFs can stabilize the surrounding dislocation network and increase the SFE (stacking faults energy) of γ′-phase. The further calculation results show that the elastic constants of Ni₃Al increase regardless of whether Re occupies the Ni position or the Al position, which is the result of Ni₃Al strengthened with Re. This study will provide experimental support for further elucidating the Re effect and help to optimize the composition design of IGT blades.