An innovative method for aluminum recycling has been boosted by research showing the microscopic changes that take place when molten alloys cool. High-speed X-ray imaging was used to record the formation of micro-crystals as alloys cool and solidify under a magnetic field. 

A mathematical model was developed to predict whether micro-crystals would form and what shape they would have. The model predicted that helical screw-like crystals would form under the influence of strong magnetic stirring, and the high-speed X-ray confirmed this occurred. Although these crystals are just micro-meters wide, they have implications for industrial-scale processes. 

Researcher Dr. Biao Cai from the University of Birmingham said, “These microscopic crystals ultimately determine the physical properties of the alloy. To be able to adjust their shape, structure and direction of growth will enable us to perfect processes for both manufacturing and recycling of metals and alloys.”