|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys II
||On the Role of the Base Elements Co and Ni in γ'-hardened Superalloys
||Steffen Neumeier, Christopher H. Zenk, Nicklas Volz, Timur Halvaci, Mathias Göken
|On-Site Speaker (Planned)
γ/γ'-Co-base superalloys share many similarities with Ni-base superalloys, but significant differences exist. To illustrate how alloy properties change, when Co gradually substitutes Ni, two series of Ni-Co-Al-W-(Cr) alloys with and without 8 at.% Cr and otherwise constant contents of Al and W were investigated with various techniques, such as electron and atom probe microscopy and neutron diffraction. The segregation tendency of elements on the dendrite scale increases with increasing Ni-content. All alloys form a γ/γ'-microstructure. The change of the partitioning behavior of elements and the change of the lattice misfit from negative on the Ni to positive values on the Co-side affects the γ'-morphology. The γ'-solvus temperature is strongly decreasing, but the γ'-fraction is slightly increasing towards the Co-side. This indicates that γ/γ'-Co-base superalloys have a great potential as wrought alloys. The creep strength changes significantly with varying Co/Ni content, however the tendency depends strongly on the presence of Cr.