Influence of High Current Impulses on Element Distribution in Creep-Deformed Single-Crystal Ni-Based Superalloys

Nickel-based superalloys are typically employed for high-temperature applications. One well-known degradation mechanism is the rafting of the gamma '-phase. In this study, it was investigated, whether a high current impulse treatment is suitable to induce changes in element distribution that are opposite to those observed during the rafting process. Thus, samples of CMSX-4 were treated with high current impulses up to 4 kA/mm2. Energy-dispersive x-ray spectroscopy measurements showed changes in element distribution due to these treatments. The changes in element distribution were observed to become more pronounced with increasing current density and partly counteracted those induced by prior creep. The extent of the compositional changes also depends on the element. Variations in the Al and Ta content showed stronger tendencies than, e.g., Cr, Co and W.