General Electric has confirmed that the 102,000lb-thrust GE9X turbofan for the Boeing 777X could feature ceramic matrix composite (CMC) materials in the second stage of the high-pressure turbine.
If selected, the GE9X would feature the first use of the exotic material in a rotating component of a turbofan's hot inner-core, and pave the way for more extensive usage in other next-generation military and commercial engines by GE.
The technology is not a trivial matter for the GE9X. By switching from a nickel-based alloy to CMCs in the second-stage turbine, GE believes the change could generate one-fifth of the anticipated 10% fuel reduction in the GE9X compared with the GE90.
CMCs improve engine performance because they are both lighter and thermally stronger, so a CMC turbine blade would not need to be cooled by diverting air from the compressor section.
The material has already been selected by GE-Snecma joint venture CFM International for the static shrouds around the second-stage turbine of the Leap family of narrowbody turbofan engines.
GE also has selected CMCs to be used in the same shrouds of the GE9X, as well as the inner and outer lining of the combustor, but never before in a rotating component of a production engine.