Aluminum vs. Composites Revisited
Aluminum producers have taken advantage of the delays in bringing composite airframes to market to come up with new lightweighting alternatives of their own.
By Myra Pinkham, Contributing Editor
Demand for aerospace alloys remains sky high as the commercial aircraft market continues to fly above the storm clouds of global economic concerns. Delays in production of the Boeing 787 Dreamliner, which breaks new ground in the use of composite airframe components, have actually given aluminum producers more time to respond to this material threat with new weight-reducing alloys and production techniques of their own.
“Boeing and Airbus both have a lot of extremely aggressive plans, but they might not all work out given all the recent economic uncertainty,” says Richard Aboulafia, vice president of the Teal Group, Fairfax, Va. “While the commercial aerospace market will likely continue to outperform the general economy, it won’t be the straight up rocket ride that some people expect.” Although orders for large commercial airliners remain strong, demand for the smaller regional and business jets continues to lag, he adds.
“Demand for commercial airliners keeps rising under the constant drive of the increase in passenger traffic, in particular in emerging economic nations,” says Christophe Villemin, president of the global aerospace division of Constellium (formerly Alcan Engineered Products). Notably, demand has been strongest for fuel-efficient, single-aisle planes, a segment that favors the use of conventional aluminum construction rather than the combination of composites and titanium that aircraft designers are using to reduce the weight of larger wide-body planes.
Overcoming the design and production challenges of adopting a new material like composites has proven frustrating for aircraft manufacturers. Indeed, the three-year delay of Boeing’s 787 brings into question the practicality of using composite materials, at least in smaller planes. Boeing’s 787 is made of about 50 percent composites, 20 percent aluminum, 15 percent titanium and 10 percent steel. By comparison, the more conventional Boeing 777 is 12 percent composites and 50 percent aluminum.
Orders for large U.S. commercial aircraft are up sharply this year, reports the Aerospace Industries Association in Arlington, Va. Both Boeing and Airbus have reported double-digit increases in orders for large civil aircraft, despite the fact the poor economy is currently keeping many domestic air travelers on the ground.
In fact, these order volumes have created record production backlogs that could take six or seven years to fill, say the experts. As a result, both Boeing and Airbus are looking to step up their deliveries by about 30 percent next year, says Keith Harvey, vice president of sales and marketing, aerospace and distribution, at Kaiser Aluminum, Foothill Ranch, Calif. Currently, each manufacturer is delivering 30 to 40 single-aisle planes and a growing number of wide-body aircraft each month. Boeing finally delivered its first 787 Sept. 26.
The industry’s two major airframe manufacturers plan to produce about 28,000 single-aisle planes over the next 20 years, as well as a large number of twin-aisle planes, says Bob Mraz, vice president of sales and marketing for TW Metals Inc., Exton, Pa. To increase its deliveries of 787s, Boeing will soon be running at least two assembly lines for that aircraft. Its new North Charleston, S.C., assembly line is expected to start delivering planes in first-quarter 2012.
Even though the number of passenger miles traveled has declined during the economic downturn, demand from commercial airlines has increased, largely due to orders from companies in developing economies such as China, India and the Middle East. “However, recently we have seen some U.S. airlines place orders as well, including American and Delta,” notes Bill Sales, senior vice president for nonferrous operations at Reliance Steel & Aluminum Co., Los Angeles.
“There seems to be a disconnect between the recent uncertainty about the economy, which is hurting the travel market, and orders for jet liners,” Aboulafia says. Jeff Luckasavage, president of ThyssenKrupp Aerospace North America, Kent Wash., attributes this, at least in part, to the increased fuel efficiency of the new planes. Fuel can account for half the cost of operating an aircraft.
Much of that efficiency comes from new engine technologies and the use of more advanced specialty metals, including titanium, in those bigger engines. Among the new planes with advanced engines are the Airbus A320 NEO (New Engine Option) and Boeing’s 737 MAX, which are 3 percent to 5 percent more fuel efficient than their predecessors. These models are likely to remain largely aluminum at least through the next decade, says Harvey at Kaiser.
The unprecedented number of new engines and new aircraft designs introduced by Boeing and Airbus, as well as Mitsubishi and Bombardier, at virtually the same time has challenged metals suppliers, says Dan Greenfield, spokesman for Allegheny Technologies Inc. in Pittsburgh. Some aerospace metals, particularly heat-treated aluminum sheet and plate, are in tight supply.
“Some aluminum companies are on controlled order entry and that is likely to continue for the foreseeable future,” says Sales at Reliance. “Titanium isn’t quite as tight as aluminum, and there hasn’t been any talk of allocation there, but they are seeing their lead times extending out.”
“We had been anticipating more demand than we are seeing,” says George Esseff, president of titanium distributor Supra Alloys, Camarillo, Calif. His company’s business, like that of other titanium suppliers, was hurt by the delay of the 787. “It has been very challenging.”
Even though Boeing has begun delivering 787s, there is likely to be some lag before aluminum and titanium orders pick up, says Gary Martin, director of high performance metals for Titanium Industries Inc., Rockaway, N.J. “Contractually, Boeing had to accept some metal regardless of what they built or shipped. They have been taking material for the last three-plus years. That means it will take some time for them to order again. There will have to be some inventory burn.”
Esseff is more optimistic. “I think Boeing has now ironed out a lot of their issues with the 787. They have 42 planes assembled, tested and ready to go. I think we will see things open up a bit once they start delivering aircraft. I anticipate there should be an upswing as early as next year,” he says.
The big question for the long-term is how Boeing’s troubled foray into new materials will affect the use of aluminum vs. composites and titanium in future aircraft platforms. “There has been a general feeling of disenchantment in the aerospace market when it comes to composites and an eagerness to look for new solutions,” Aboulafia says.
“I really don’t think there was any dampening of enthusiasm for composites just because of the 787 delays,” Luckasavage counters. “There will continue to be a materials battle for certain sections of various aircraft. It will go back and forth between composites and aluminum,” with both finding their place, he says.
“The 787 delay was a wakeup call for aluminum producers, one that has been heard,” declares Mraz at TW Metals. “It gave them the time to get their next round of new alloys ready, which can compete anywhere composites are used.”
Materials decisions for the 787 were made many years ago, notes Kevin Lowery, a spokesman for Alcoa Inc., New York. Given what was available at the time, it made sense for Boeing to go with composites, especially for a twin-aisle jet. “But since that time, [aluminum producers] have made many innovations, both in new alloys and joining techniques,” he says. “We have come to the OEMs with total solutions and have gotten positive response.”
Mick Wallis, president of Alcoa’s North American rolled products unit, claimed at a recent press conference that third-generation aluminum-lithium alloys can achieve up to 10 percent weight savings at a 30 percent lower cost compared with current composite-intensive planes.
Constellium has touted its next-generation Airware aluminum-lithium alloy product, which has a lower density, higher stiffness and better damage tolerance than previously available alloys. When combined with advanced welding and high-performance redesign of the aircraft structure, Airware can deliver a 25 percent weight reduction, the company claims.
Some aircraft makers already have reconsidered aluminum for certain projects, Lowery says, most notably the Mitsubishi Regional Jet, which was originally designed with composite wings. Making this change particularly noteworthy is the fact that Mitsubishi is a composite supplier to the aerospace industry.
In addition, Bombardier is using an aluminum intensive airframe for its new C-Series plane, Gulfstream is using aluminum for its 360 plane and China’s AVIC may also favor aluminum for its ARJ-21 regional jet, although it has made no formal announcement yet.
Martin at Titanium Industries says titanium producers are also developing new, more cost-effective alloys that will help the material make new inroads in aircraft designs, either alone or in combination with composites. Titanium is lighter and stronger, but must overcome a cost disadvantage in applications where it competes with aluminum. Aluminum sells for $4 to $5 a pound, vs. $10 to $12 a pound for titanium.
Whether aluminum or composites win the materials race over the long run—and they both undoubtedly will garner a healthy share of the growing aerospace market—aluminum producers have just about all the business they can handle today. Harvey expects customers to remain on controlled order entry for some time. Esseff predicts titanium could see a 15 to 20 percent improvement in 2012. “If the stars all line up correctly, it could even be better than that,” he says.