CompositesWorld
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JUNE 2017 32 CompositesWorld INSIDE MANUFACTURING Disruptive designs for composites operation in 1093°C zones. » Aircraft engine manufacturers have spent years investigating exotic materials, in response to passenger, regulatory and cost pressures, that might reduce engine noise, emissions and specific fuel consumption (a measure of the efficiency of an engine design with respect to thrust output, largely related to mass or weight) in commercial passenger planes. Toward these ends, they have scrutinized super heat-resistant materials that show potential for reliable performance at the extreme temperatures (~1093°C) generated during the intended lifecycle and variety of conditions undergone by aircraft engines (see Learn More, p. 36). Among the candidate materials, which include nickel super- alloys, one winner appears to be ceramic-matrix composites (CMCs), different forms of which have been in R&D; for years at General Electric (GE Aviation, Cincinnati, Ohio, US), Rolls-Royce (Manchester, UK), Pratt & Whitney (Hartford, CT, US) and other major aircraft engine manufacturers. High-temperature pioneer Composites Horizons Inc. (CHI) in Covina, CA, US, a high-temper- ature materials pioneer, won an intensely contested contract from GE Aviation in 2010 to build CMC mixer, centerbody and engine core cowl components for GE's newly FAA-certified Passport 20 engine, destined for Bombardier's (Montreal, QC, Canada) long- range business aircraft, the Global 7000 and Global 8000, and similar models from other OEMs. At this writing, CHI has produced more than 300 ceramic components under the GE contract. Acquired in 2016 by Precision Castparts (Portland, OR, US), part of the Berkshire Hathaway Group, CHI has focused on high-temper- ature composites since its founding in Covina, CA, in 1974. It began with available high-temperature organic polymers. "We were one of the early innovators of polyimide composites in the late 1970s and early 1980s, and have worked with engine and aircraft manufacturers on all the key polyimide materials," says Jeff Hynes, CHI's president and CEO. But these, too, had their limits. "Our impetus for inves- tigating and pursuing higher temperature materials in inorganic ceramics, outside of the organic world, was the consistent and persis- tent interest of our engine customers in higher temperature realms than the organic composites could reach. So, our entire operation has really focused on high-temperature materials." (See Learn More.) With its high-temperature experience and a clear, growing demand in aerospace and industrial markets for the highly-prized characteristics of hot-zone materials, CHI made a strategic decision to fully invest in CMC technology. However, "You can't simply take these materials and put them on polymer matrix composite Ceramic-matrix composites: Hot engine solution By Donna Dawson / Senior Writer Emeritus