Aluminum-lithium alloys may be used for Boeing 777X

The stretched 777-9, the biggest twin-engine model Boeing Co. is planning to build, may be partly fabricated from a new breed of aluminum-lithium alloys, lighter and stronger than the aerospace-grade aluminum now used. Boeing gave the green light to the model on Wednesday.

Yes, these new alloys do include lithium, the highly reactive metal that caused Boeing such problems with the 787’s lithium-ion batteries

The promise of aluminum lithium alloys is so interesting to the aerospace industry that an entire panel was devoted to the subject at the Pacific Northwest Aerospace Alliance annual conference in Lynnwood, in February.

Executives from Dutch aluminum company Constellium and from Alcoa Aerospace updated the audience, mostly made up of aerospace suppliers.

“As aircraft design requirements change, aluminum is still innovating, and we expect to be here for a long time,” Brandon Bodily, an Alcoa engineer, told the crowd. “New aluminum lithium alloys can offer 1 to 2 percent improvements for long-range aircraft.”

Alcoa is pouring money into facilities to produce aluminum lithium alloys, expecting it to be incorporated in new aircraft including Boeing’s planned 777 and perhaps the 737 Max. Boeing hasn't said whether or not it will use aluminum-lithium alloys in either plane.

Alcoa is now building a $90 million aluminum-lithium ion production plant in Lafayette, Ind. When completed next year, the new factory will be able to produce 200,000 metric tons of the alloys a year.

“Our primary role as aerospace solution providers is to help the OEMs (original equipment manufacturers) reduce fuel consumption per seat mile,” said Eric Roegner, president of Alcoa Forgings and Extrusions, in a statement at the factory ground breaking last year. “Our aluminum-lithium supply chain will be the premier operation in the world, and this specialty alloy will be flying on the next generation of aircraft.”

Alcoa also is expanding another aluminum lithium facility, located in Upper Burrell, Penn.

Currently Boeing’s popular 777 300-ER weighs 370,000 pounds when empty, and carries 386 passengers in a standard configuration. The new stretched 777-9 is intended to carry 21 more passengers.

Alcoa claims that using its aluminum-lithium alloys can lower an aircraft’s weight by 10 percent, and manufacturing and repair costs by 30 percent.