%0 Journal Article
%A Volz, N.
%A Zenk, C. H.
%A Cherukuri, R.
%A Kalfhaus, T.
%A Weiser, M.
%A Makineni, S. K.
%A Betzing, C.
%A Lenz, M.
%A Gault, B.
%A Fries, S. G.
%A Schreuer, J.
%A Vaßen, R.
%A Virtanen, S.
%A Raabe, D.
%A Spiecker, E.
%A Neumeier, S.
%A Göken, M.
%T Thermophysical and Mechanical Properties of Advanced Single Crystalline Co-base Superalloys
%J Metallurgical and materials transactions / A
%V 49A
%N 9
%@ 1543-1940
%C Boston
%I Springer
%M FZJ-2018-03299
%P 4099-4109
%D 2018
%X A set of advanced single crystalline γ′ strengthened Co-base superalloys with at least nine alloying elements (Co, Ni, Al, W, Ti, Ta, Cr, Si, Hf, Re) has been developed and investigated. The objective was to generate multinary Co-base superalloys with significantly improved properties compared to the original Co-Al-W-based alloys. All alloys show the typical γ/γ′ two-phase microstructure. A γ′ solvus temperature up to 1174 °C and γ′ volume fractions between 40 and 60 pct at 1050 °C could be achieved, which is significantly higher compared to most other Co-Al-W-based superalloys. However, higher contents of Ti, Ta, and the addition of Re decrease the long-term stability. Atom probe tomography revealed that Re does not partition to the γ phase as strongly as in Ni-base superalloys. Compression creep properties were investigated at 1050 °C and 125 MPa in 〈001〉 direction. The creep resistance is close to that of first generation Ni-base superalloys. The creep mechanisms of the Re-containing alloy was further investigated and it was found that the deformation is located preferentially in the γ channels although some precipitates are sheared during early stages of creep. The addition of Re did not improve the mechanical properties and is therefore not considered as a crucial element in the design of future Co-base superalloys for high temperature applications. Thermodynamic calculations describe well how the alloying elements influence the transformation temperatures although there is still an offset in the actual values. Furthermore, a full set of elastic constants of one of the multinary alloys is presented, showing increased elastic stiffness leading to a higher Young’s modulus for the investigated alloy, compared to conventional Ni-base superalloys. The oxidation resistance is significantly improved compared to the ternary Co-Al-W compound. A complete thermal barrier coating system was applied successfully
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000440714700028
%R 10.1007/s11661-018-4705-1
%U https://juser.fz-juelich.de/record/847991