Novel Co-Ti-V-base superalloys reinforced by L12-ordered γ′ phase. (January 2018)

• Record Type: Journal Article
• Authors: Ruan, J.J.; Liu, X.J.; Yang, S.Y.; Xu, W.W.; Omori, T.; Yang, T.; Deng, B.; Jiang, H.X.; Wang, C.P.; Kainuma, R.; Ishida, K.
• Is Part Of: Intermetallics. Volume 92(2018:Jan.)
• Page Start: 126
• Page End: 132
• Publication Date: 2018-01
• Subjects: Cobalt-base superalloys -- Compression test -- L12 compound -- Phase diagram; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2017.09.015
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: The influences of alloying elements Al and Ni to a Co-Ti-V master alloy on microstructures, phase stabilities and high-temperature mechanical properties have been investigated. A two-phase microstructure γ/γʹ with ultrahigh γʹ volume fraction was designed in the Co-Ti-V (master alloy), Co-Ti-V-Al (Al-modified) and Co-Ti-V-Ni (Ni-modified) alloys. Al shows a slight tendency to partition into γʹ, while Ni exhibits almost equal distribution between the γ and γʹ phases. Al is found to increase the volume fraction and solvus temperature of γʹ. The solvus temperatures of γʹ in the master alloy, Al-modified and Ni-modified alloys exceed that of Co-9Al-9W alloy (1000 °C) by 91, 112 and 82 °C, respectively. The flow stresses of the designed alloys exhibit an anomalous positive dependence on temperature rising from 600 to 750 °C. The strengths of the master alloy and Ni-modified alloys are not only higher than that of traditional Co-base superalloy MAR-M 302 at the temperature ranging from 700 to 1000 °C, but also comparable with that of the commercial Ni-base superalloy IN-939 between 850 and 1000 °C. In conclusion, the present Co-Ti-V-base alloys reinforced by γʹ are suggested as potential candidates for high-temperature utilizations. Highlights: The Co-Ti-V-base alloys strengthened by L12 -ordered phase are designed successfully. The Co-Ti-V-base alloys designed possess high Tsolvus -γ′ combined with mild Tm . The Co-Ti-V-base alloys display attractive high-temperature strength.