High Resolution Analysis of Elemental Partitioning in Nickel-Base Superalloy Welds Using Atom Probe Field Ion Microscopy
Weldability of single-crystal and directionally solidified Ni-base alloys is important for repairwelding of failed components. During welding, phase decomposition and subsequent microstructure development may occur under non-equilibrium conditions. The final microstructure and phase composition of γ and γ' phases in these welds control the weld properties. Previous work used atom-probe field-ion microscopy (APFIM) for characterizing commercial single-crystal alloys. This work summarizes the microstructural development in PWA-1480 [Ni - 11.5 at. % Cr - 11.0% A1 - 5.1% Co - 1.3% W - 1.9% Ti - 4.0% Ta] electron beam (EB) welds and CMSX-4 [Ni - 7.5 at. % Cr - 12.7% A1 - 9.9% Co - 0.38% Mo -2.1% W - 1.3% Ti - 2.2% Ta - 0.95% Re - 0.034% Hf| pulsed laser (PL) welds.In both PL and EB welds, a dendritic mode of weld solidification was observed.