To investigate the effect of Ta addition on the evolution of MC carbides in the Ni16Co10W8Cr5Al alloy during homogenization at 1 200 ℃ and to elucidate the role of Ta in the stability of MC carbides, thermodynamic calculations, microstructural observations, image statistical analysis, and energy-dispersive spectroscopy (EDS) were used. The results revealed the effect of Ta on the compositional changes and coarsening of MC carbides after homogenization at 1 200 ℃ for 10 h. Thermodynamic calculations indicated that the addition of Ta enhanced the stability of MC carbides and increased their complete dissolution temperature. Statistical results showed that, after heat treatment at 1 200 ℃ for 10 h, both the area fraction and size of MC carbides increased; however, the changes in MC carbides in the 0Ta alloy were significantly greater than those in the 2Ta alloy. EDS elemental mapping revealed that the distribution of C was essentially consistent between the core and shell regions of the MC carbides, indicating that the core-shell structure mainly originated from the different distributions of metallic elements, including Ti, Nb, Ta, W, and Mo, between the core and shell regions. After Ta addition, Ta was evidently enriched in the MC-carbide regions and altered the distribution of Ti, Nb, W, and Mo, giving the particles a Ti-Nb-Ta multicomponent enrichment characteristic, thereby enhancing their stability and suppressing their coarsening during homogenization. Overall, Ta addition improved the stability of the MC carbides and retarded elemental redistribution and carbide coarsening during homogenization.
Peng P , Liu Z J , Xu Y L , et al . Effect of Ta on solidification characteristics and mechanical properties of DZ411 Ni-based superalloy [J]. China Foundry , 2023 , 20 ( 5 ): 376 - 386 .
Li Y S , Dong Y W , Jiang Z H , et al . Hot deformation characteristics of GH4975 nickel-based superalloy in the coexistence region of γ and γ′ phases [J]. JOM , 2024 , 76 ( 9 ): 5133 - 5148 .
Wang Y L , Tan Y , Zhang Y , et al . Hot deformation behavior and dynamic recrystallization mechanisms of GH4975 alloy prepared by electron beam smelting layered solidification [J]. Materials Characterization , 2023 , 202 : 113034 .
Jiang H , Xiang X M , Dong J X . The morphology and characteristics evolution of MC carbide during homogenization in hard-to-deform superalloy GH4975 [J]. Journal of Alloys and Compounds , 2022 , 929 : 167086 .
Zhao G D , Zang X M , Sun Y X , et al . Effect of homogenization treatment on the microstructure evolution and hot deformation behavior of hard-deformed superalloy GH4975 [J]. Materials Science and Engineering: A , 2025 , 942 : 148711 .
Gao X Y , Zhang L F . Effect of Ta addition on primary MC carbide in Ti-Nb-Mo-W-alloyed superalloy [J]. Materials Characterization , 2024 , 211 : 113918 .
Zhang W Y , Li L H , Su H Y , et al . Effects of Ta addition on the solidification and homogenization of Ni-based superalloy GH4065A [J]. Materials , 2026 , 19 ( 5 ): 1002 .
Jin X , Zhao Y S , Chen W , et al . Microstructural characterization of defects and secondary phases in (Ti, Ta)C-type carbides in nickel-based superalloys [J]. Materials , 2026 , 19 ( 9 ): 1875 .