US aluminium castings producer Eck Industries and Canada's Imperial Mining are building prototypes for a battery box for electric vehicles (EVs) made from a high-strength scandium-modified aluminium alloy, potentially opening up a significant new end-use market for scandium.
Imperial began working with Eck in May to investigate adding critical mineral scandium to a widely available commercial alloy known as AlMag, or alloy 535 — a lightweight aluminium alloy that contains 7pc magnesium. Eck already uses AlMag in several of its commercial products for the automotive sector. Adding scandium increases the yield strength, opening up new structural applications in the high-growth EV market.
Castings have not been seen as an obvious route for developing the use of scandium in alloys. "While this is true in some cast alloys it is not universally true," Eck vice-president for research and development David Weiss said. "This work, entailing innovative casting methods and heat treatment, lays the groundwork for additional improvement in cast alloys".
Part of the appeal of castings technology is that it makes it possible to produce extremely complex parts at a lower cost.
"The test data show that we have met or exceeded the material properties requirements for EV battery boxes for a major North American automotive manufacturer," Imperial chief executive Peter Cashin said. "We will now begin working with Eck on prototyping components."
The potential of aluminium-scandium alloys for the aerospace and transportation sector has been understood for decades, but never commercialised outside the defence sector. Instead, scandium developed niche applications in electronics, lasers, sporting equipment and, more recently, in clean energy. The main development barrier has been the lack of a clear path to the supply growth and the production cost transparency needed for bigger applications. Until recently, scandium was only produced in small quantities as a by-product from mining operations in Asia-Pacific and Russia. But a major investment by UK-Australian mining company Rio Tinto, which built a 3 t/yr demonstration scandium oxide plant in Quebec this year, has increased interest in all the potential applications.
Rio Tinto sold the first batch of scandium-aluminium alloy billet produced at its plant in Sorel-Tracy to Australian additive manufacturer and developer Amaero in March. Amaero is processing it into 3D printing powder for its high operating temperature Amaero Al alloy for lightweight applications.
By Caroline Messecar