Aluminium has an obvious role to play in the transition towards lower-carbon manufacturing. Lightweight, versatile and recyclable, it is already fundamental to automotive manufacturing, particularly in structural applications where reducing mass can contribute to vehicle efficiency.
But being recyclable does not automatically make a material circular.
Today, most of the aluminium recovered from vehicles at end-of-life in the UK follows a process that means it can’t be reused in similar high-value structural applications. Vehicles are shredded; different grades and compositions of aluminium become mixed; material gets downgraded into lower-value applications or exported.
At the other end of the process, automotive OEMs continue to specify high-quality primary aluminium for their most demanding structural components, bringing with it a significant embodied carbon footprint.
That creates a disconnect. Aluminium that’s still valuable leaves the automotive supply chain at the end of one vehicle’s life, while new, carbon-intensive primary material is introduced to manufacture the next.
To achieve true circularity for aluminium, and begin to change the future of our industry, we need to close that loop.
Keeping Aluminium at High Value
Some see the challenge as simply increasing the quantity of aluminium that gets recycled – but there’s much more to it. The aim must be to retain the quality and value of used aluminium, so that recovered material can be used again in demanding applications.
To achieve this, we need a new approach to how vehicles and components are treated at end of life.
Rather than relying on indiscriminate shredding, smarter dismantling and material selection should be implemented to identify and separate aluminium streams more effectively. This would help to create a broader and more reliable stock that can remain within the UK and be reused for high-value manufacturing projects.
However, material separation only solves part of the problem.
One of the traditional barriers to greater recycled content in structural aluminium castings is the presence of impurities, and the industry has worked for years to remove or tightly control those elements more effectively, to recreate the characteristics associated with primary material.
Sarginsons’ work through the £5.8 million PIVOT programme is challenging that philosophy. Rather than continually fighting impurities, we are exploring how we can work with them.
That means understanding the composition of recovered material, how different elements influence its behaviour and how the material itself can be developed with recycling in mind. The precise alloy compositions emerging from that work remain proprietary to the project, but the wider principle we’re championing is that recycled aluminium should not automatically be regarded as an inferior substitute for primary material.
If its characteristics can be understood, predicted and engineered appropriately, it creates a route towards much greater use of recycled content in structural applications.
Designing Around the Material
This becomes particularly powerful when material development is considered alongside component design, rather than as a separate exercise.
PIVOT brings together Sarginsons, Aston Martin, Siemens, Brunel University and GESCRAP to connect casting expertise, vehicle engineering, simulation, materials development and circularity within the same process.
At Sarginsons, we have spent more than 20 years collecting physical testing and microstructural data to understand how aluminium behaves locally – or heterogeneously – throughout a casting. That unique capability enables us to map variable mechanical properties and use those properties within finite element analysis, rather than representing an entire component using a single conservative material value.
Combined with topology optimisation technology, this allows engineers to put material where it is genuinely required for performance and remove it where it is not.
Our first virtual concepts developed as part of the PIVOT programme demonstrate that potential. Cast aluminium front and rear subframes developed for a demonstrator vehicle for a major British OEM are currently 17% and 35% lighter respectively than the components they are intended to replace, while delivering equivalent strength and crashworthiness.
That matters to circularity because reducing carbon should not be considered purely in terms of the source of the metal. We must first ask how much material a component really needs, how efficiently it can be manufactured, how much recycled content it can incorporate and, ultimately, what happens to that material at the end of the component’s life.
Considering those questions together creates the potential for a much more significant carbon reduction than addressing them in isolation.
A UK Circular Supply Chain
Our ambition is to establish a pathway towards structural castings produced from up to 100% recycled aluminium, with the potential to reduce embodied carbon by more than 90%. But what’s equally important to us is where that material goes after use.
A genuinely circular model would see aluminium recovered intelligently from end-of-life sources, selected and processed according to its material characteristics, then returned to UK manufacturers for the next generation of high-value components.
There are wider industrial benefits to that approach. A domestic circular supply chain reduces dependence on carbon-intensive primary aluminium and creates an opportunity to strengthen the UK’s sovereign manufacturing capability while making much better use of a resource already in circulation.
Sarginsons’ ongoing Future Foundry programme is intended to help industrialise that thinking. Backed by £650,000 through the UK Government’s DRIVE35 programme, we are currently undertaking a scale-up feasibility study that will define how our Coventry facility could introduce next-generation, low-carbon and digitally enabled manufacturing equipment, with the longer-term ambition of creating a near-zero-carbon casting hub.
Ultimately, however, achieving circularity will require more than investment in a single foundry.
Vehicle designers, OEMs, dismantlers, recyclers, materials specialists and manufacturers must begin to think about aluminium as part of one connected system. Decisions made when a vehicle is designed affect how easily its materials can be recovered years later, just as decisions made during dismantling determine whether that material can return to a high-value application or be lost to the structural supply chain.
The technology to change that trajectory is beginning to emerge; the next step is to stop viewing recycled aluminium as a compromise and start engineering our products and processes around its potential.
