Aluminum-lithium alloys may be used for Boeing 777X

 Boeing officially enters the fray against Airbus in the large twin-jet category with Boeing's planned 777X, a secondary theme is that Boeing is continuing to bet on aluminum.

But not your parents’ aluminum.

The stretched 777-9, the biggest twin-engine model Boeing Co. (NYSE: BA) 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 Wednesday.

Yes, these new alloys do include lithium, the highly reactive metal that caused Boeing such problems with the 787’s lithium-ion batteries. (Boeing’s 787 Dreamliner has been grounded for more than three months due to charring of two lithium-ion batteries, and only recently was cleared to return to service by the Federal Aviation Administration, after an expensive battery fix.)

But don’t worry, when lithium and aluminum are mixed together, the resulting alloy has no propensity to combust.

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 Bodilyan, an Alcoa engineer, told the crowd. “New aluminum lithium alloys can offer 1 to 2 percent improvements for long-range aircraft.”