Effect of Induction Heating Temperature on the Microstructures and Properties of GH4169 Alloy

The effect of induction heating temperature on the microstructures and properties of GH4169 nickel-based superalloy was investigated. Both electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were applied to analyze the microstructure. The results showed that the induction heating temperature had a promoting influence on the evolution of static recrystallization (SRX) and the optimization of grain boundary characteristics distribution (GBCD). After induction heating, the coincidence site lattice (CSL) boundaries were mainly Σ3 boundaries, and the main formation mechanism was the growth accident model. With the increasing heating temperature, the SRX behavior was well developed with a gradual increase in the fraction of Σ3 boundaries. This indicates a 'symbiotic relationship' between the SRX grains and Σ3 boundaries. Moreover, it was found that the ductility and corrosion resistance of the alloy were improved with the increasing temperature. This is mainly due to the fact that the SRX behavior can effectively improve the uniformity of the microstructure and eliminate the residual stresses. Meanwhile, the high fraction of Σ3 boundaries disrupts the connectivity of the random grain boundary network, ultimately enhancing the corrosion resistance of the GH4169 alloy.