Microstructure and Mechanical Properties of a MP159 Superalloy after Pre‐tensile Deformation and Subsequent Annealing

Pre‐tensile deformation and subsequent annealing treatments are conducted on a MP159 superalloy. It is shown that pre‐tensile deformation can significantly improve the strength of the alloy with obvious sacrifice of the ductility. The subsequent annealing treatment further improves the strength of the alloy but without the consumption of the ductility. The strength and ductility synergy are due to the annealing‐induced stacking faults (SFs) and γ′ nanoprecipitates. The length and density of the annealing‐induced SFs increase with increasing the imposed pre‐tensile strain, and the formation of the SFs contributes significantly to the strain‐hardening rate and the ductility of the superalloy.