Microstructure and deformation mechanism of Ni-based wrought superalloys for A-USC power plants: a review

Ni-based wrought superalloys are a type of superalloy produced through casting-forging processes, and usually their high-temperature performance is strongly influenced by microstructure and deformation mechanism. The typical microstructure of Ni-based wrought superalloys after heat treatments comprises equiaxed grains, numerous annealed twins, carbides within the grain interior and/or at grain boundaries, and spherical γ′ precipitates (typically comprises around 20% of their volume). The common deformation mechanisms in Ni-based wrought superalloys mainly include anti-phase boundary formed by paired dislocations shearing γ′ phase, stacking fault formed by single dislocation shearing γ′ phase, dislocation bypassing γ′ phase (precipitation-strengthened) and dislocation entanglement, dislocation networks (solid solution strengthened). In this paper, the microstructure and deformation mechanism of tensile and creep in Ni-based wrought superalloys for Advanced ultra-supercritical (A-USC) power plants are reviewed, for the two prominent areas of current research, Ni–Fe-based wrought superalloys exhibit superior processability and cost-effectiveness compared to Ni–Co-based wrought superalloys, thereby offering a more advantageous solution.