Microstructure and Mechanical Properties of a Novel γ′-Strengthened Multi-Component CoNi-Based Wrought Superalloy

To reveal the deformation behavior of a novel γ′-strengthened multi-component CoNi-based wroughtWrought superalloySuperalloys, the tensile propertiesTensile properties from room temperature to 850 °C and creep propertyCreep properties under 725 °C/630 MPa were studied. The results show that after hot forgingHot forging and sub-solvus solution plus two-step aging heat treatmentHeat treatment, the grain sizeGrain size of the investigated alloy is uniform, accompanied by the bimodal distribution of γ′ precipitatesPrecipitates. Elements such as Co, Cr, and Mo segregate within the γ phase, whereas Al, W, Ni, Ti, and Ta exhibited segregationSegregation in the γ′ precipitatePrecipitates. In comparison with typical wroughtWrought superalloysSuperalloys U720Li and WaspaloyWaspaloy, the investigated alloy exhibits enhanced yield strength at 750–850 °C, which may be associated with the alloy’s larger grain sizeGrain size and the increase in the intermediate temperature flow stress anomaly inherent to Co-based alloys. Meanwhile, the creep propertyCreep properties of the investigated alloy surpasses those of alloys U720Li and WaspaloyWaspaloy, which is primarily attributed to its larger grain sizeGrain size and relatively higher γ′ volume fraction. Additionally, the lower stacking faultStacking faults energy of the alloy facilitates the formation of stacking faultsStacking faults and micro-twinsMicro-twins, further enhancing its creep propertyCreep properties. The findings of this study will hold importance for the further optimization of CoNi-based wroughtWrought superalloysSuperalloys.