Enhanced strength-ductility and stress-rupture properties of a Ni-based superalloy via nanotwins and stable γ’ particles

Here, we alter the alloying elements of GH4742 superalloy by means of domain-knowledge informed thermodynamic calculation to reduce the stacking fault energy of the γ matrix and enhance the stability of γ’ particles. Increasing Co and Cr concentrations with Mo substitution by W induces the formation of high-density stacking faults and nanotwins, while reducing the coarsening rate of γ’ particles during tensile testing at 760°C and stress-rupture loading at 760°C/480 MPa. Thus, the yield strength, working-hardening capacity, and stress-rupture life are simultaneously improved, achieving the synergic enhancements in strengths-ductility and stress-rupture properties at elevated temperature.