* Constellium among leading metal suppliers for planes
* Sees aerospace growth slowing as composites take off
* Says all to play for in materials for planes in 2030s
* R&D includes mixed metal-fibre parts
By Gus Trompiz and Laurence Frost
PARIS/VOREPPE, France, June 20 (Reuters) - All-metal planes are a thing of the past, but evolving aluminium-based materials remain in the race with composites to supply the next generation of jets, according to aluminium maker Constellium.
The growing use of carbon composites in aircraft has eroded aluminium's dominance as the material of choice for planemakers.
This has left aerospace demand for aluminium trailing behind booming use of the metal in the car industry, where aluminium supplied by the likes of Arconic, Aleris International and Constellium has played the challenger to steel.
Constellium projects aluminium demand from aerospace will grow by an average 2 percent over the next five years, about half of what it has seen historically.
That compares with the 10-20 percent annual growth rate it anticipates from the car sector in the coming years.
The group is "not hoping for" a return to all-aluminium plane bodies, after composites established their role, but sees much to play for as planemakers study options for jets that will take to the skies in the 2030s, Chief Executive Officer Jean-Marc Germain said.
"I think like everything in life there is a moment of excitement about composites, justifiably so, but sometimes the pendulum will swing as well," he said in an interview coinciding with the Paris Airshow.
Composites have clearly shown their attractiveness in wing strength. But design setbacks in some parts of the plane have already let aluminium claw back share in recent jet programmes, Germain said, declining to give specific details.
The tried-and-tested qualities of aluminium have been talked up by metal suppliers as planemakers focus on meeting tight delivery schedules and ambitious production targets.
But aluminium is not just a fallback option, according to Germain, who said developments in lighter alloys and combining of different materials would keep metals in the running as planemakers draw up new designs.
At Constellium's research centre in Voreppe, located in what was the heartland of the French aluminium industry in the Alps, test projects range from combining fine layers of metal and glass fibre, to gluing aluminium parts together with resin to dispense with rivets that weigh more.
Lighter alloys have already earned Constellium and its peers market share on recent jet programmes by narrowing the weight gap with lightweight composites. But they also cost more, eroding aluminium's price advantage over composites, while plastic materials continue to benefit from innovations.
A new single-aisle airliner produced by Russia's United Aircraft Corporation boasts composite wings made using a cheaper manufacturing process that could help open up the middle of the jet market to composite-driven designs. (Reporting by Gus Trompiz; Additional reporting by Laurence Frost; Editing by Mark Potter)