%0 journal article %@ 0925-8388 %A Wang, L.,Song, L.,Stark, A.,Liu, Y.,Oehring, M.,Lorenz, U.,Pyczak, F. %D 2019 %J Journal of Alloys and Compounds %N %P 880-886 %R doi:10.1016/j.jallcom.2019.07.121 %T Identification of Laves phases in a Zr or Hf containing γ-γ′ Co-base superalloy %U https://doi.org/10.1016/j.jallcom.2019.07.121 %X ZrCo2 and HfCo2 Laves phases were found and characterized in γ-γ′ Co-base superalloys using high-energy X-ray diffraction, energy dispersive X-ray spectroscopy and transmission electron microscopy. They formed during casting and are stable during long-term annealing at 900 °C. The ZrCo2 phase with a cubic MgCu2-type structure exhibits numerous nano-twins and stacking faults, while HfCo2 has a hexagonal MgNi2-type structure instead of MgCu2-type in contrast to literature. Their chemical compositions strongly deviated from stoichiometry and significant amounts of Al and W are contained in these phases. These could affect the atomic radius ratio and valence electron concentration and thus change the structure of the Laves phases.