Effect of electric current on secondary phase dissolution and elements migration behavior of a Ni-based single crystal superalloy

The second phase dissolution and elements migration behavior of a nickel-based single crystal superalloy during solution heat treatment with direct current were investigated for simplifying and shortening the solution heat treatment of the Ni-based single crystal superalloy. The results showed that the electric current solution heat treatment improved microstructural homogenization as well as the distribution of alloying elements, especially for the refractory metal W and Mo. The microsegregation ratios for Mo and W after electric current solution heat treatment at 1230 °C for 4 h are near those without electric current at 1250 °C for 4 h. The electric current accelerated the γ′ phase dissolution process, and the γ′ phase could be completely dissolved at a lower treatment temperature or within a shorter treatment time under electric current solution heat treatment with direct current. A microcosmic current model was proposed to analyze the effect of the electric current on the solution heat treatment of the Ni-based single crystal superalloy.