Grain boundary segregation in a Ni–Fe-based (Alloy 718) superalloy

The characterization of the grain boundaries of Ni–Fe-based superalloy (Alloy 718) after service in a compressor has been performed using the high resolution methods: three-dimensional atom probe and transmission electron microscopy. Atom probe analysis shows a segregation of P (∼2 at.%), B (∼2 at.%), C (∼0.2 at.%) and Mo (∼8 at.%) at the grain boundaries. These grain boundaries have a zigzag-like shape which follows the regular arrangement of small γ″ precipitates.