Effect of homogenization treatment on the microstructure and creep properties of additively manufactured Inconel 718 alloy modified by Ti2AlC inoculants

Nickel-based superalloys are well known for their exceptional creep resistance at elevated temperatures. The addition of TiC to additively manufactured Inconel 718 (IN718) has shown promise in improving the potential for enhanced creep properties. However, the effect of conventional homogenization treatment strategies on TiC-modified additively manufactured IN718 has yet to be fully explored. In this study, we investigate the effect of a tailored homogenization treatment on laser powder bed fusion (L-PBF)-fabricated Ti₂AlC-modified IN718 (Ti₂AlC/IN718) to optimize its creep performance. The results demonstrate that the optimized homogenization treatment significantly enhances the creep resistance of Ti₂AlC/IN718. Notably, samples homogenized at 1200 °C and 1250 °C exhibit remarkable improvements in creep rupture life, with values reaching 217 h and 262 h, respectively, which is significantly higher than the creep rupture life of L-PBF fabricated IN718 reported in the existing literature. The enhancement in creep resistance is attributed to significant changes in both grain structure and the Laves phase. The homogenization treatment facilitates a transition from a columnar to an equiaxed grain structure, thereby reducing the vulnerability of grain boundary regions to cavitation. Furthermore, the effective dissolution of the Laves phase at grain boundaries decreases the nucleation sites for void formation, enhancing creep life. The solubility of Nb in the matrix promotes the formation of the primary strengthening phase γ′′, thereby further improving the creep resistance. This research offers a new homogenization treatment strategy for enhancing the creep properties of Ni-based superalloy composites.