Project aims to develop next generation of high-strength aluminium alloys

High-strength aluminium alloys produced from completely recycled metals could be developed as a result of a UK-led research partnership.

high-strength aluminium
Pic: Brunel University

Aluminium production consumes 3.5 per cent of the world’s electricity supply, while producing one per cent of global carbon dioxide emissions.

However, the metal is theoretically infinitely recyclable, with its recycling consuming just five per cent of the energy needed to produce the metal in the first place. Over one billion tonnes of aluminium has been produced since 1908, of which over 75 per cent remains as accessible stock.

Now, in a bid to reach a full circle aluminium use and recycling system, researchers at the Brunel Centre for Advanced Solidification Technology (BCAST) at Brunel University, working with Netherlands-based aluminium products manufacturer Constellium, have established a strategic research partnership.

The partnership will develop high performance aluminium alloys, and investigate their applications in lightweight vehicle construction, according to Prof Zhongyun Fan, project leader and director of BCAST.

Aluminium alloys have a range of benefits including low density, high strength, and high corrosion resistance. As a result, demand for aluminium products is increasing, particularly in the transport industry.

Brunel University’s casting techniques could lead to lighter and recyclable car components

However, even with the reduced weight offered by aluminium car components, a vehicle must be run for 10,000 miles before it becomes effective in reducing carbon dioxide emissions, said Fan. That is because the process of mining and producing aluminium is extremely energy-intensive, he said.

“But if you use recycled aluminium, from day one you are reducing carbon dioxide emissions,” he said.

The STEP (Strain Enhanced Precipitation) project will develop a new generation of alloys with ultra-high strength – approximately twice that of conventional aluminium alloys – as well as good ductility, high crashworthiness and high thermal conductivity.

The researchers will use a combination of production techniques, including deformation, and a reduction in the crystal size of the alloys developed, to increase the overall strength of the metal, said Fan.

The researchers also plan to develop a novel melt conditioned direct chill (MC-DC) casting process, in which liquid metal is intensively sheared before solidification.

The MC-DC casting process produces aluminium feedstock with much higher quality.

“It has much finer crystals, resulting in higher strength and making it easier to process later on,” said Fan.

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