Morphology evolution of γ′ phase in K465 nickel-base superalloy during laser forming repairing

Laser forming repairing (LFR) was performed on the damaged K465 nickel-base cast superalloy parts. LFR presented the uneven microstructure characteristics at different positions of the LFRed K465 superalloy, such as substrate zone (SZ), heat affected zone (HAZ), and repaired zone (RZ), which experienced the different thermal history. Compared with the coarser γ′ precipitates in the cast SZ, the γ′ precipitates in RZ were refined obviously. As for HAZ, γ′ phase presented an incomplete solid solution and reprecipitation growth characteristics. This led to an increase in the microhardness from SZ, HAZ to RZ.