High-throughput assessment of Nb, Co, Ti, and Al effects on microstructure and mechanical properties in wrought nickel-based superalloys

The influence of Nb, Co, Ti, and Al on the microstructural evolution and mechanical properties of GH4061 superalloy was simultaneously investigated using diffusion multiple techniques combined with double aging heat treatment. Co exhibited the highest penetration depth with monotonic concentration decrease, significantly inhibiting the formation of needle-like δ phase and reduced the precipitation size of the γ′ phase. Nb diffusion formed distinct layers with clear interfaces, promoting substantial γ′′ phase precipitation, while simultaneously enhancing hardness through solid solution strengthening. Ti and Al diffusion generated substantial diffusion layers containing Ti-Ni enriched needle-like η phases and enhanced γ′ phase growth, characterized by increased size and volume fraction compared to the base alloy. In contrast to the base alloy, this diffusion layer was devoid of phases enriched with Nb. Mechanical property analysis demonstrated that high concentrations of Nb, Al, and Ti enhanced alloy hardness through various strengthening mechanisms, whereas increased Co content diminished the size of the γ′ phase at the interface, resulting in reduced hardness. This high-throughput experimental approach significantly reduced experimental workload while enabling detailed analysis of varying element concentrations on microstructure and properties.