LOS ANGELESGeneral Electric will develop Huntsville, Alabama-based production facilities dedicated to making materials for the ceramic matrix composites (CMC) that will feature in the new generation of CFM Leap and GE9X engines.

                                                                       

The adjacent factory sites—the first factories of their type and scale in the U.S.—will produce the silicon-carbide (SiC) materials that form the basis for CMCs, a low-weight, high-temperature-resistant ceramic to be used extensively in the hot section of the two new engine families. GE—together with its CFM joint-venture partner Snecma—is banking heavily on the benefits of CMCs to deliver better efficiency and fuel-burn performance, and the dedicated facilities are required to support the huge production ramp-up of the new engines starting in 2018.

Together with the Leap, which requires 18 CMC turbine shrouds per engine, and the GE9X, which will use the new material in the combustor and for 42 nozzles in the high-pressure turbine section, GE expects demand for CMCs to grow tenfold by the mid-2020s. Current orders and commitments for the Leap engine, which will power the Airbus A320neo, Boeing 737MAX and Comac C919, stand at more than 9,500. In comparison, orders for the GE9X, which will power the Boeing 777X, exceed 700 engines. Production of the Leap engine is set to rise rapidly from 2016 onward, reaching over 1,000 engines per year by 2018, and more than 1,800 per year by 2020.

The ability to indigenously manufacture the raw material for CMCs “is very much our competitive strategy for our aviation commercial and military business,” according to GE Aviation Vice President-CMC Program Sanjay Correa. “The plants will produce a silicon-carbide matrix with a silicon-carbide fiber. We will make, in effect, a tape which goes to the fabrication plant in Asheville, North Carolina, and on to Lafayette, Indiana, for Leap, and for GE9X to Durham, North Carolina.” The opening of the Alabama sites “is very much a production-execution phase” of the Leap and GE9X build-up, he added.

The finished tape, or tow, “looks like a stiff black tape, and we cut ply shapes from that,” Correa said. At the Asheville facility, established in 2014 by GE, the tape is cut and laid up into structures, before being fed into furnaces. There, “liquid silicon drips in and reacts with excess carbon. It sets to make stoichiometric silicon carbide under a melt infiltration process. GE has put a lot of effort into this in the last 15 to 20 years,” he said.

GE is investing more than $200 million in the Huntsville site, with $21.9 million in supporting funding from the U.S. Air Force Research laboratory (AFRL). Construction of the two plants is expected to get underway in mid-2016, with full completion by the first half of 2018. Although the Air Force currently has no known plans to introduce CMCs into either production or planned military engines, AFRL has been closely involved in propulsion-related CMC research and test work. GE says the development of the Alabama facility effectively opens the door to further military applications, and “will dramatically increase U.S. capability to produce SiC ceramic fiber capable of withstanding temperatures of 2400F.”

GE previously tested CMC components in its now-abandoned F136 alternate engine for the F-35 Joint Strike Fighter, and in 2014, ran rotating hot section parts made from CMCs in an F414 low-pressure turbine. The company is also using the advanced ceramic material in its GE3000 turboshaft for the U.S. Army’s ITEP program, and incorporated CMCs in its FATE (Future Affordable Turbine Engine) turboshaft demonstrator for the U.S. Army.

Although limited volumes of SiC material have been produced for initial testing, development and Leap production in the U.S. and France, the only large-scale SiC ceramic fiber factory in the world is currently operated by NGS Advanced Fibers in Japan, which is a joint company of Nippon Carbon, GE, and Snecma’s parent company Safran.