The U.S. aluminum giant Alcoa, materials-technology company GTM Advanced Structures and scientists at Delft University of Technology in the Netherlands have patented a fiber metal laminate (FML) called CentrAl reinforced aluminum, or CentrAl, for use in aircraft manufacture.
CentrAl provides some 25 percent more tensile strength than high-strength aluminum alloys, is extremely resistant to metal fatigue and is highly damage-tolerant.
“We think you can save 600 to 800 kilograms in a large aircraft (over carbon-fiber composite) — we estimate that the saving could be around 15 to 20 percent of the weight of the wing,” he said. This hasn’t been proved, because nobody has yet made a wing using the new material, but it is likely that a wing made using CentrAl would be much easier to repair and maintain than a carbon-fiber composite wing.
CentrAl starts with layers of glass fiber/epoxy sandwiched between layers of aluminum. Between the fiber and the aluminum are layers of a proprietary resin-rich material that its developers call “BondPreg.” These layers cause the aluminum to adhere to the glass fiber and also help to spread stress loads evenly throughout the laminate. Thick layers of advanced aluminum, attached strongly to the CentrAl laminate using BondPreg, form the outside of the sandwich.