Suppressing recrystallization in a cast Ni-based single-crystal superalloy by electro-pulsing treatment

Suppressing recrystallization in Ni-based single-crystal superalloys is critical to maintaining single-crystal integrity and high-temperature performance. Here, electro-pulsing treatment with a negligible temperature rise was introduced as a preconditioning strategy and was found to suppress recrystallization during subsequent solution heat treatment. Compositional analysis shows no detectable long-range solute redistribution occurred during electro-pulsing treatment. While microstructural and residual stress characterizations revealed reduced geometrically necessary dislocation density, weakened dislocation entanglement, and remarkedly relieved residual stress. These findings demonstrate electro-pulsing as a promising route for recrystallization control in Ni-based single-crystal superalloys, and identify residual stress and dislocation structures as key factors governing recrystallization susceptibility.IMPACT STATEMENTThis work identifies electro-pulsing as a new approach to suppress recrystallization in as-cast Ni-based single-crystal superalloys, and reveals residual stress and dislocation structures as key drivers of recrystallization.