Material has always been at the center of aviation advancement, dating back to the Wright Brothers, who used wood, steel and canvas to kick off the era of powered flight.
As aviation pushed the envelope of speed, range and altitude, engineers needed metal alloys like aluminum, titanium and other high-temperature metals. Next, carbon fiber composites and even light metal alloys were introduced.
To maximize even greater performance in today’s state of the art jet engines, temperatures in parts of the hot section must run hotter than the melting point of metal. The need for a next generation material system that can take the heat.
Enter ceramic matrix composites — or CMCs — which are a super material that is as tough as metals, but only one-third as heavy and can operate at 2,400 degrees Fahrenheit—500 degrees higher than the most advanced alloys.
CMCs unlock new efficiencies that allow jet engines to use less fuel and run cleaner but the process of mass-producing them is complicated. In fact, less than 20 years ago, a study was published by the Institute of Defense Analysis titled, “Will Pigs Fly Before Ceramics Do?”
The overall assessment from the study concluded that CMCs were not ready for use in “high payoff” jet engine components and unless a more radical, unconventional approach was taken to incorporate CMCs by engine designers, there may be more pigs flying than ceramics in the future.
“GE carries a tradition for being on the cutting edge of pioneering advanced material systems – including composites,” said Mike Kauffman, general manager of GE Aviation’s CMC Integrated Product Team. “GE developed Carbon Fiber fan blades during a time when many in the aviation industry doubted if the technology could ever be used in service. We needed these lighter fan blades for the development of the GE90 – world’s largest and most powerful engine at the time. Without them, the engine would have been too heavy.”
GE was very aware of the challenges with CMC material. Scientists at their Global Research Center in Niskayuna, NY, spent more than a decade working to develop the material system before the study was even written.
GE Aviation cracks the CMC code
After years of research and testing, GE and its partners have cracked the code to mass-producing CMC material and are in the final stages of establishing a vertically-integrated supply chain to control every phase of its manufacture – from raw material production to finished parts.
During the last decade, GE Aviation has spent more than $1.5 billion to bring advanced CMC technology to market. Beyond GE’s Global Research Center in Niskayuna, this investment includes four production facilities:
- A CMC laboratory at its headquarters in Evendale, Ohio, to develop CMC production designs
- A low-rate production facility in Newark, Delaware, for CMC raw material and components
- A full-rate production raw material facility in Huntsville, Alabama that will begin producing material this year
- A full-rate production raw material facility in Toyama, Japan operated by NGS Advanced Fibers, joint company of Nippon Carbon, GE, and Safran of France
- A full-rate production facility in Asheville, North Carolina, that is producing CMCs parts for engines including the CFM LEAP and GE9X
“We are linked tightly between GRC all the way through to our Asheville production, and we are using the scope of GE to maximize both our speed and efficiency,” said Kauffman. “It has been an amazing undertaking. New material systems aren’t introduced often, so this is an exciting time to be a part of this history.”
CMC parts have already surpassed 1.5 million hours of flight time in commercial engines. LEAP engines flying on Airbus, Boeing and COMAC aircraft –and GE Aviation is developing the largest aircraft engine in the world – the GE9X – which has five CMC parts and enters service on the Boeing 777X around the end of the decade. CMCs are also being incorporated in GE’s military engine architecture.
“Not that I’m keeping score but we beat the pigs to the air,” Kauffman said.
The sky is not the limit for GE Aviation’s CMC business. CMCs are showing promising potential for other applications ranging from heat shield systems for spacecraft and fuel rod cladding for nuclear reactors.
“We really are just scratching the surface for CMC demand,” Kauffman said. “We’re exploring opportunities but right now we have an amazingly talented CMC team that focused on delivering parts for our aviation customers.”