|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys II
||Properties of γ'-phase in L12-precipitation Hardened Co-base Alloys with Different W-content
||Yuzhi Li, Uwe Lorenz, Steffen Neumeier, Andreas Schreyer, Andreas Stark, Li Wang, Florian Pyczak
|On-Site Speaker (Planned)
While Co-Al-W alloys hardened by a L12-type γ'-phase show microstructural similarities to Ni-base superalloys, they differ in many significant details. For a knowledge based development of alloys derived from the Co-Al-W alloy system, it is necessary to investigate and understand these unique features especially of the γ'-hardening phase. Here results about a range of properties in Co-Al-W alloys with different W contents are shown with an emphasis on the long term stability of the γ'-phase, the lattice mismatch, creep properties and plastic deformation mechanisms during creep. It is found that the γ'-phase is metastable and transforms to D019 Co3W after extended annealing. The lattice mismatch is positive up to the γ'-solvus temperature, which influences the development of the microstructure during high temperature deformation. During creep cutting of the γ'-precipitates by partial dislocations generating extended planar faults is a common feature already in the early stages of creep.