Aluminium makers fight plastic planes with new alloys

Metal is staging a comeback, at least in the aerospace world, where aluminium has been challenged by newfangled carbon-composites in the industry's perpetual war on weight.

As plane makers showed off their latest carbon-plastic jetliners at the Paris Airshow this week, metal firms lobbied hard for new, lighter aluminium alloys.

Aleris International, for example, is developing an aluminium-magnesium-scandium alloy that it says is 5 percent lighter than conventional aircraft aluminium and could be ready for later production of next-generation Airbus A320neo and Boeing 737MAX jets.

Nearly 90 percent of the 9,600 aircraft on order with Boeing and Airbus are metallic, said Ingrid Jorg, senior vice president of Aleris, mainly because smaller jets won't use composite fuselages for decades, if ever.

"If you don't expect single-aisle planes to turn to composites before 2030, then there's a lot of demand," she said.

The advent of composites with the Boeing 787 a decade ago looked likely to undercut the aerospace aluminium industry. But years of research into lighter, more useable alloys is coming to fruition. Their use could keep aluminium demand strong for years, particularly in Asia.

The new materials face tests in labs and regulatory approval. They are also are more expensive than conventional aluminium. But aluminium's long use in aerospace means many properties are well known. And some new alloys can compensate for high cost with better manufacturing use.

The Aleris aluminium-magnesium alloy can be welded, for example, replacing millions of fasteners on Airbus and Boeing jets, says Jorg. Some aluminium-lithium alloys can cut weight by 8 percent over traditional alloys.