The system Co–Ti–Cr was recently identified as a very promising base for low mass-density Co-based superalloys. This study presents the influence of quaternary alloying additions on the thermophysical and mechanical properties of a Co–11Ti–15Cr model superalloy. Al, Ta, Re, and W were selected as a starting point for alloy development as they represent important alloying elements in both Ni-based and Co–Al–W-based superalloys. Microstructure analysis reveals that the addition of only 1 at.% of either of these elements causes the formation of different undesired intermetallic phases in addition to γ and γ′ phases, which is in agreement with thermodynamic calculations. However, a diffusion couple between the Co–Ti–Cr and a Co–Al–W–Ta alloy suggests that the tolerance for alloying elements without destabilizing the γ/γ′ two-phase microstructure is higher when they are present in a certain ratio. Energy-dispersive X-ray spectroscopy shows that Cr and Re are enriched in the γ phase, whereas Ti and W preferentially partition to γ′. All alloying elements increase the yield strength at room temperature, but are disadvantageous at 1000 °C. Re and W retain their strengthening effect up to 900 °C.
CITATION STYLE
Zenk, C. H., Volz, N., Bezold, A., Huber, L. K., Eggeler, Y. M., Spiecker, E., … Neumeier, S. (2020). The Effect of Alloying on the Thermophysical and Mechanical Properties of Co–Ti–Cr-Based Superalloys. In Minerals, Metals and Materials Series (pp. 909–919). Springer Science and Business Media Deutschland GmbH. https://doi.org/10.1007/978-3-030-51834-9_89
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