Influence of elevated Co and Ti levels on polycrystalline powder processed Ni-base superalloy. (December 2014)

• Record Type: Journal Article
• Authors: Jones, N. G.; Christofidou, K. A.; Mignanelli, P. M.; Minshull, J. P.; Hardy, M. C.; Stone, H. J.
• Is Part Of: Materials science and technology. Volume 30:Number 15(2014)
• Page Start: 1853
• Page End: 1861
• Publication Date: 2014-12
• Subjects: Nickel-base superalloy, -- Cobalt, -- Titanium, -- Mechanical properties; Materials science -- Periodicals; Microstructure -- Periodicals; Metallurgy -- Periodicals; 620.1105
• DOI: 10.1179/1743284714Y.0000000509
• Languages: English
• ISSNs: 0267-0836

Abstract

Abstract : The influences of elevated Co and Ti levels on the mechanical properties of the Ni-base superalloy RR1000 have been investigated. Following heat treatment, the modified alloys had the typical γ–γ′ microstructure, with γ′ precipitate sizes comparable to similarly heat treated RR1000, but with a slightly higher volume fraction. The modified alloys exhibited a higher proof stress than RR1000 across the entire 20 to 800°C temperature range investigated. Superior creep rupture lives, when compared to RR1000, were observed in the modified alloys at 700°C, but not at 750°C, where extensive precipitation of topologically close packed σ phase occurred on the grain surfaces. The formation of this deleterious phase was linked to Cr and Mo enrichment of the γ matrix, caused by the elevated Co and Ti additions.