| Title |
Effect of Additive Elements and Content on Thermodynamic Solidification Pathway and Cast Fluidity of TiAl alloys |
| Authors |
최광수(Kwangsu Choi) ; 양현석(Hyunseok Yang) ; 정우철(Woo-Chul Jung) ; 김성웅(Seong-Woong Kim) ; 김채원(Chae-won Kim) ; 공만식(Man-Sik Kong) |
| DOI |
https://doi.org/10.3365/KJMM.2026.64.10.882 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
TiAl alloy; Casting fluidity; Alloy design; Gravity casting |
| Abstract |
In this study, the correlation between the behavior of individual additive elements and spiral casting fluidity in TiAl alloy systems was systematically investigated using a gravity precision casting process. The content and type adjustments of substitutional elements (Al, Nb, W, Cr) were evaluated to elucidate their specific effects on liquidus temperature variations, the thermal interval controls of two-phase regions and compositional supercooling induced by solute rejection. These thermodynamic parameters were identified as the primary factors that collectively dictate melt fluidity flow resistance and ultimate mold filling capacity by modifying the primary solidification pathways and phase stability. Furthermore, the precipitation behavior of secondary phases and solid solution effect of interstitial and ternary elements (B, Si and C) during high-temperature solidification were quantitatively analyzed, revealing their distinct roles in altering dendritic growth kinetics and liquid-solid interfacial mobility. Based on these thermodynamic solidification pathway control mechanisms, a novel multi-component Ti-Al-Nb-W-Si-C alloy was designed, exhibiting a significantly refined solidification microstructure and superior casting fluidity compared to the commercial 4822 alloy. Additionally, the homogenized Ti-Al-Nb-W-Si-C alloy exhibited a yield strength of 313 MPa at 1000 °C, ensuring exceptional high-temperature strength retention. The present work demonstrates the feasibility of alloy design that simultaneously satisfies both the castability and high-temperature mechanical properties required for advanced high-temperature structural materials. |