The effect of Ni:Co ratio on the elemental phase partitioning in γ-γ′ Ni-Co-Al-Ti-Cr alloys
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Llewelyn, S., Christofidou, K., Araullo-Peters, V., Jones, N., Hardy, M., Marquis, E., & Stone, H. (2017). The effect of Ni:Co ratio on the elemental phase partitioning in γ-γ′ Ni-Co-Al-Ti-Cr alloys. Acta Materialia, 131 296-304. https://doi.org/10.1016/j.actamat.2017.03.067
Atom probe tomography has been used to characterise the effect of varying Ni:Co ratio on elemental phase partitioning at 800 °C in γ-γ′ alloys derived from the Ni-Co-Al-Ti-Cr system. In all alloys tested, Al and Ti were found to partition preferentially to the γ′ phase, whereas Co and Cr partitioned preferentially to the γ phase. However, above a critical Co content (~19 at.%), the extent of partitioning of Al and Ti to the γ′ phase reduced. Conversely, Cr partitioned more strongly to the γ phase with Co additions of up to ~19 at.%, above which this preferential segregation was less pronounced. This non-monotonic trend of elemental partitioning behaviour with increasing Co concentration was attributed to a transition in the chemistry of the L1$_2$ γ′ phase from Ni$_3$(Ti, Al) to (Ni, Co)$_3$(Ti, Al) and thus to a change in its solute solubility.
atom-probe tomography, nickel, cobalt, superalloys, phase composition
Is supplemented by: https://doi.org/10.17863/CAM.8774
This work was supported by the Rolls-Royce EPSRC Strategic Partnership under EP/H022309/1 and EP/M005607/1, by the University of Michigan College of Engineering (funding) and by the Michigan Center for Materials Characterization (instruments).
UNIVERSITY OF BIRMINGHAM (FB EPSRC) (EP/H022309/1)
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External DOI: https://doi.org/10.1016/j.actamat.2017.03.067
This record's URL: https://www.repository.cam.ac.uk/handle/1810/265069