Allotropic transformation induced stacking faults and discontinuous coarsening in a γ-γ′ Co-base alloy. (April 2015)

• Record Type: Journal Article
• Authors: Bhowmik, Ayan; Neumeier, Steffen; Rhode, Sneha; Stone, Howard J.
• Is Part Of: Intermetallics. Volume 59(2015:Apr.)
• Page Start: 95
• Page End: 101
• Publication Date: 2015-04
• Subjects: A. Intermetallics -- B. Diffusion -- B. Phase transformation -- D. Planar faults -- F. Electron microscopy, transmission; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2014.12.013
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: The stability of a Co-based alloy designed to possess a microstructure comprising of L 12, γ′ Co3 Ti-type precipitates embedded in an A 1, γ Co solid solution matrix has been investigated. The alloy showed acute microstructural instabilities upon ageing at 700 °C, resulting in the degeneration of the γ-γ′ aggregate into i) a faulted Co-based martensite and Co3 Ti and ii) a lamellar aggregate of A 3-Co and Co3 Ti. The faulted Co-based phase was formed by isothermal diffusionless transformation of the metastable A 1-phase, whilst the lamellar aggregate was a discontinuous reaction product. Highlights: High temperature long-term stability of Co–Cr–Ti–Mo alloy has been studied. The alloy initially comprised of an A1–Co matrix and L12 -Co3 Ti precipitates. Microstructural instabilities caused by continuous and discontinuous reactions.