GE spent the last two decades developing the
next-generation material, called ceramic matrix
composites (CMCs). It is strong, tough, and also
amenable to mass production. CMCs are made from
silicon carbide matrix toughened with coated
fibers made from the same material.
They are already working inside CFM’s new LEAP
jet engines and advanced gas turbines. The
material is light, one-third of the weight of
nickel super-alloys, but extremely durable. It
can work in temperatures as high as 2,400F, well
beyond any advanced alloy.
“Silicon carbide is fantastic,” Vartuli says.
“It is the lightest and strongest material that
can work at high temperatures. But if you make a
coffee mug out of it, it will break when you
drop it.” That’s where the fibers with GE
engineered coatings come in. They make CMCs
behave like a metal when they’re hit. “There’s
no concern about catastrophic failure,” Vartuli
says.
Being both tough and light is a powerful
combination. “If you take a pound off something
that’s spinning, you get a whole cascade
effect,” Vartuli says. “That pound works out to
be usually about three additional pounds you can
take off from the support structure and bearings
because of a smaller centrifugal force.”
|