Farnborough Air Show

Alcoa Says Bring On Those Aerospace Materials Challenges

 - July 9, 2016, 9:30 AM
Embraer’s E-Jet E2 family of medium-range jetliners is designed to replace the company’s current E-Jet series. Alcoa is now Embraer’s sole provider of aluminum sheet and plate for the new type’s wing skins and fuselage components.

“Airframe and Engine OEMs—bring your challenges to us. We have the material expertise, resources and the personnel to ‘crack the code,’” promised Alcoa executive Eric Roegner. The senior executive is here at the Farnborough International Airshow (Chalet C27 and Hall 4 Stand B120) with the U.S. company’s management team, and news on Alcoa’s commitment to additive technologies (3D printing), castings, hybrids, extrusions and machined components. Late last month during a media event at the Alcoa Technology Center in New Kensington, Pennsylvania, just outside Pittsburgh, Roegner told reporters, “We’re truly material agnostic.”

Kicking off the event, Ray Kilmer, executive v-p and chief technology officer at Alcoa, pointed out the ubiquity of Alcoa’s expertise on lightweight metals and other materials. “If it moves, we’re on it,” he boasted, adding that Alcoa products are found not only in structures, but engines as well, dating back to the Wright Brothers, whose four-cylinder engine had an aluminum crankshaft. “Ninety-three percent of aluminum alloys that have ever flown are from Alcoa,” Kilmer said.

Alcoa is in the midst of a complex corporate restructuring and rebranding phase. Expected to be completed sometime in the second half of this year, the changeover will see Alcoa’s aerospace businesses become part of a new business entity known as Arconic. Focused in part on materials for aeronautical structures, engines (primarily turbine blades), industrial turbines and aerospace fasteners, Arconic’s future focus builds on Alcoa’s rich history of supplying lightweight metals for flying machines. The separation is currently pending approvals from the Alcoa board of directors, the U.S, internal revenue service and other regulatory agencies. For now, at least, the company is still “Alcoa.”

3D Printing Advantage

Roegner explained Alcoa’s “material agnostic” stance, meaning it now counts additive manufacturing—better known as 3D printing technology—to its mix of products and services. “We’re known for our legacy capabilities with sheet, machining, casting, hybrid, extrusion; and now we’ve added printing and powder technology,” he said.

Alcoa has doubled down on its commitment to 3D printing technology with last week’s opening of an entirely new powder atomization building at its New Kensington facility. Building F replaces an older structure with a top-tier 3D metal powder producing facility, where proprietary titanium, nickel and aluminum powders can be produced in quantities and blends optimized for designing, manufacturing, and certifying aerospace parts.

Announced just months ago in September 2015, the new building is part of a $60 million investment in additive manufacturing materials. Alcoa chairman and CEO Klaus Kleinfeld said, “We are combining our expertise in metallurgy, manufacturing, design and product qualification to push beyond the possibilities of today’s 3D printing technologies for aerospace and other growth markets.”

Alcoa sees its advantage in 3D printing for the aerospace industry as a “one-stop shop” for aircraft and engine designers and manufacturers. Rod Heiple, director of R&D (and chief of “disruptive technologies”) at the Alcoa research center said the potential for additive manufacturing in aerospace is immense, but echoed Roenger’s comment that the relatively new industry is currently in the “Wild West” phase of expansion. Heiple said, “Today’s 3D printing materials work [for some applications], but aren’t optimized for aerospace. Alcoa has the background to understand the interdependencies of all requirements for materials in the aerospace field. As researchers, we get excited by design opportunities with additives. But it’s not a simple process, especially with aerospace.”

Heiple illustrated his point with a diagram showing how product design (working with customers to develop problem-solving parts) is entwined with expertise in materials.  Resins and powders for the 3D printing process need to be appropriate for aerospace applications. There are also important manufacturing concerns, such as ensuring the part can be safely and cost-effectively manufactured with current machines—and perhaps more important—with an eye toward future advances in manufacturing technology. Finally, there is certification and qualification. In aerospace, more so that just about any other field, the path toward acceptance of a part by certification authorities must be painstakingly detailed and fully documented.

“That’s where Alcoa has the experience and the history,” said Heiple.

Not All About 3D Printing

Not all of what’s new is quite so disruptive. Old-school aluminum sheet for airframes has also come a long way. In fact, one airframe manufacturer has already answered Roegner’s call for challenges in “cracking the code.”

Late last month, Alcoa announced Brazilian airframer Embraer had signed a $470 million multi-year contract with Alcoa’s aluminum sheet and plate division as sole provider for wing skins and fuselage sheets on the E-Jet E2 family of airliners. This represents a shift by Embraer from using “commodity” sheet aluminum, to a proprietary Alcoa formula. Launched at the 2013 Paris Air Show, the E2 narrowbody medium-range jet is scheduled for certification and entry into service in 2018.

Embraer believes the market segment in which the E2 fits is expected to sell 6,350 new aircraft in the next two decades, and the Brazilian OEM lays claim to better than half of the current orders with its current crop of E-Jets and counts on maintaining that market share with the E2 going forward.

Mark Stuckey is Alcoa’s v-p, global aerospace and defense. “Flat roll” sheet aluminum is one of his specialties, and in a time when all the buzz seems to be about carbon fiber composites and/or 3D additive technologies, he pointed out that there are situations “where aluminum is still best.” In fact, he said, much of the structure of a composite airframe such as the Boeing 787 Dreamliner is still aluminum—including wing ribs and large base structural components such as spars and wing center sections. As far as skins, in particular, wing panels must be flexible, particularly in tension on the bottom and compression on top, for when wings bend in flight. Advanced aluminum formulas, perhaps incorporating a blend of titanium and/or nickel, rival composites when it comes to optimizing the skins for performance, strength, weight and cost, he said.

Fuselage skins have their own particular requirements. For example, the wider (and larger) the skin, the fewer fasteners are required, reducing weight and also rendering the structure less susceptible to problems with expansion and contraction from pressurization cycles. Stuckey pointed out that business jets, which typically fly at higher altitudes and have correspondingly more pressurization systems, benefit most from advanced formulas and production processes in fuselage skins.

Alcoa is in the process of installing a $190 million aluminum “stretcher” that will be capable of processing the largest cross-section of sheet plate, ever. The stretching process essentially grips each end of a sheet of metal and pulls until the entire sheet expands by “a few percent.” This aligns the stresses within the metal ensuring it will not curl up “like a potato chip,” said Stuckey. The new stretcher can not only accommodate thicker sheets, but also larger panels. It’s scheduled to enter service in mid-2017.

Stuckey also discussed how Alcoa is now becoming more involved in delivering completed or pre-machined parts, as opposed to simple plates. He also talked about Alcoa’s advances in hybrid composite/metal sheeting, known as fiber-metal laminates, or FMLs. “There’s less corrosion with FMLs,” he said, “and that extends inspection intervals, saving the cost of maintenance. It’s lighter, too.”

Explaining why it’s difficult to place a quantitative number on how much weight advanced structures can save, Stuckey and Roegner said that increasing strength in one area of an airframe can enable multiple other structures to be made lighter.