The effect of gamma matrix channel width on the compositional evolution in a multi-component nickel-based superalloy

High-temperature diffusion affects the long-term stability of superalloys and hence their service life. Yet, details of the mechanisms remain elusive. Here, the gamma-gamma' microstructure itself is used as a nanoscale diffusion couple to study the diffusion of alloying elements within narrow and wide gamma channels during annealing for up to 100 h at 750 degrees C in a nickel-based superalloy. Predictions from thermodynamic and kinetic calculations are compared to near-atomic experimental measurements as a function of the gamma channel width. An overlooked width-dependence of compositional evolution is revealed that may directly affect the microstructural and compositional predictions of service life of nickel-based superalloys.

Automated summary

This study uses the gamma-gamma' microstructure as a nanoscale diffusion couple to investigate the diffusion behavior of alloying elements in nickel-based superalloys under different widths of gamma channels, revealing a width-dependent compositional evolution that may impact the microstructural and compositional predictions of service life for nickel-based superalloys.