Alcoa ups the ante against composites

Aluminum giant Alcoa (H5 F220) is here exhibiting a fuselage section manufactured with advanced aluminum-lithium alloy sheet that was stretch-formed on existing tooling by Spirit Aerosystems’ factory in Wichita, Kansas. U.S.-based Alcoa is targeting the next generation of single-aisle aircraft (with a clear focus on Boeing’s expected decision this year) as the potential first applications. It is touting the merits of new-technology metals against composites–lower weight, better fuel efficiency, reduced cost and less risks in production–promised for aircraft entering into service before 2020.

“We learned the hard way that we did not innovate enough,” Kevin Lowery, communications director for Alcoa’s global rolled products, told AIN. He was referring to the decisions by Boeing and then Airbus to dramatically increase the proportion of composite materials on their new widebody programs–respectively, the 787 and the A350 XWB. After this wake-up call, research and development in aluminum has accelerated over the past decade, notably at Alcoa’s research center in Pittsburgh, Pennsylvania.

According to Tony Morales, global marketing director for aerospace aluminum, the empty weight of rolled products, with Alcoa’s new alloys, will be cut by six to 10 percent. The starting point for this is the new material’s lower density, 3 to 7 percent below that of today’s metals. On top of that, Alcoa engineers have devised ways to add structural reinforcements only where they are really needed. Also, thanks to better crack propagation resistance, some parts can be made thinner and lighter.

Other improvements have further helped to fuel consumption for aircraft. First, applying these new design approaches (including the more precisely located reinforcements) allow Alcoa to achieve more aerodynamic geometries, such as a higher wing aspect ratio.