Future materials: aluminum lithium, standard metals or composities

The Farnborough Air Show isn’t just about orders, though these get all the sex and headlines.

While we weren’t at the show, we had a telephone interview with a company called Constellium, previously known as Alcan. Constellium spoke at the February conference of the Pacific Northwest Aerospace Alliance, with which we are involved. We were particularly interested in talking with Constellium because it is a major supplier of Aluminum-Lithium, an alternative material to standard aluminum and a competing material to composites.

Constellium’s Al-Li combines other processes, including a design for recycling, and is named AirWare. Airbus, Boeing and Bombardier are among their key customers, and it is Constellium that is providing the materials for the CSeries. It’s also a supplier on the Airbus A350 (internal components, not the fuselage).

As Airbus and Boeing looked at the A320neo and 737 MAX, and as Boeing is looking at the 777X, we asked them about the prospect of using Al-Li. This is lighter than standard aluminum, more durable, less susceptible to corrosion and enabled 12 years between major maintenance overhauls compared with the 6-8 years now.

But Al-Li is more difficult to work with than standard aluminum. Boeing’s Mike Bair told us in an interview that Boeing considered Al-Li back in the 1990s when designing the 777 but it was too difficult and costly to manufacture. Since then, he praised the producers for strides. There are mixed reports what material will be used for the 777X fuselage: standard metal or Al-Li. The Seattle Times reported the airplane will have Al-Li. We’ve been told it won’t. But with the airplane still months and perhaps a year from launch, there is plenty of time to decide.

Airbus, in an interview at the Paris Air Show last year, said it was evaluating Al-Li for the A320neo. The A320ceo is heavier than the competing Boeing 737 and the re-engine adds about 4,000 lbs. Using Al-Li would mitigate some of this weight. We haven’t heard if Airbus might go ahead with Al-Li, but we’re leaning toward concluding that it won’t.

Boeing told us it will not switch to Al-Li for the MAX because the manufacturing process is just enough different that it would add complexity and cost to the current tooling and procedures.

Al-Li vs composites is a competition that will likely be fierce when it comes time for Airbus and Boeing to design the next clean-sheet airplanes, presumed to be the New Small Airplane, or replacement for the current 737/A320 class. (Boeing may have a new clean-sheet for the 757 class; it has a New Airplane Study underway for this, but the market may be too narrow when one considers the 737-9 MAX and A321neo will do 95% of what a 757 can do.)

Composites, selected for the 787 and A350 XWB fuselages and wings, offer advantages over standard metal fuselages that have been well documented and need not be repeated here. But Airbus and Boeing question the efficiency and benefits of down-scaling composites to 737/A320 category airplanes. Boeing apparently became convinced: Jim Albaugh, former CEO of Boeing Commercial Airplanes, said the New Small Airplane would have been composite, but the ability to produce it at a rate of 60 per month remained a challenge. Boeing went with the MAX instead.

Vistagy, a composite manufacturer near Boston, told us nearly two years ago, that the down-scaling challenges were met and that production rates were the issue. Autoclaves are very costly and so is the manufacturing process. There is actually less industrial waste than traditional aluminum manufacturing, but the materials are generally more hazardous—though there have been strides on this score.

This is the background that intrigued us when we had the opportunity to speak with Constellium’s Simon Laddychuk, VP of Manufacturing Global Aerospace and Director of Technology. Read more