On the Solidification and Phase Stability of a Co-Cr-Fe-Ni-Ti High-Entropy Alloy

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2014-01, Vol.45 (1), p.184-190
• Main Authors: Yeh, An-Chou, Chang, Yao-Jen, Tsai, Che-Wei, Wang, Yen-Chun, Yeh, Jien-Wei, Kuo, Chen-Ming
• Format: Article
• Language: English
• Subjects: Alloy solidification; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromium; Cobalt base alloys; High temperature; Materials Science; Metallic Materials; Metallurgy; Microstructure; Nanotechnology; Partitioning; Partitions; Physical metallurgy; Segregations; Single crystals; Structural Materials; Surfaces and Interfaces; Symposium: High Entropy Alloys; Thin Films
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-013-2097-9

In the present study, a Co1.5CrFeNi1.5Ti0.5 high-entropy alloy has been investigated for its high-temperature microstructural stability. This material is shown to possess mainly a face-centered cubic (FCC) structure; the η phase is present at the interdendritic region in the as-cast condition, and it is stable between 1073 K and 1273 K (800 °C and 1000 °C); γ′ particles are found throughout the microstructures below 1073 K (800 °C). Segregation analysis has been conducted on a single crystal sample fabricated by a directional solidification process with a single crystal seed. Results show that Co, Cr, and Fe partition toward the dendritic region, while Ni and Ti partition toward the interdendritic areas. Scheil analysis indicates that the solid–liquid partitioning ratio of each element is very similar to those in typical single crystal superalloys.