Energy - Research - Department of Materials Science & Engineering

Nanoscale visualization of early g/g'-phase separation

Supported by the National Science Foundation, Grant DMR-0241928

Booth-Morrison C, Weninger JW, Mao Z, Noebe RD, Seidman DN, Acta Mater (2008), doi:10.1016/j.actamat.2008.03.016

The efficiency of turbine engines employing concentrated multicomponent Ni-based superalloys is directly related to the engine operating temperature, and hence to the microstructural stability of Ni-based alloys. Efforts to improve the stability of these materials require an understanding of the kinetic pathways that lead to precipitation at operating temperatures up to 1373 K. Atom-probe tomography (APT) is used to study nanoscale g’-Ni3(Al,Cr) precipitation in a model Ni-7.5 Al-8.5 Cr at.% alloy aged for 1024 hours at 873 K. The spheroidal g’-precipitate of radius ~ 9 nm imaged above by APT is delineated from the g-matrix phase by a 10.5 at.% aluminum isoconcentration surface: Al atoms (red), Cr atoms (blue), Ni atoms are omitted for clarity.

Effects of a Ta addition on the temporal evolution of a model Ni-Al-Cr superalloy

Supported by the National Science Foundation, Grant DMR-0241928

Booth-Morrison C, Noebe RD, Seidman DN. to be presented at Superalloys 2008 (2008).

Refractory additions to Ni-based superalloys such as Ta increase the maximum operating temperature of turbine engines, thus reducing CO2 emissions from both aerospace and land-based turbine engines. After aging for 64 h at 1073 K, g’(L12) -precipitates from a model Ni-10.0 Al-8.5 Cr-2.0 Ta at.% alloy designed to study the effects of Ta on Ni-based superalloy microstructure are cuboidal and aligned along the elastically soft <001>-type directions, as imaged by SEM and atom-probe tomography: Al atoms (red), Cr atoms (blue), Ta atoms (yellow), Ni atoms are omitted for clarity.