Secret to Balancing Performance and Sustainability

The trend towards electrification is reshaping industries like automotive and telecommunications. Electric vehicles (EVs) and high-performance electronics require materials that manage heat effectively, ensuring reliability and efficiency. Moreover, reducing weight is crucial for extending the range of EVs and improving device energy efficiency. Aluminium alloys offer an excellent solution, but the key to maximizing their benefits is selecting the correct alloying elements and casting method.

Embracing Higher Iron Content for Sustainability

Iron (Fe) in aluminium alloys has traditionally been viewed cautiously due to its potential to reduce thermal conductivity. However, a nuanced approach reveals several sustainability advantages associated with higher iron content:

• Recyclability: Iron is abundant and widely recycled, reducing the need for primary material extraction and enhancing the alloy’s overall sustainability.
  
  
• Cost-Effectiveness: Incorporating more iron can lower production costs, making the material more affordable and accessible for various applications.
  
  
• Strength and Durability: Higher iron content can improve the mechanical properties of aluminium alloys, enhancing their durability and lifespan. This contributes to sustainability by reducing the frequency of replacements and repairs.

Understanding Thermal Conductivity

Thermal conductivity in metals primarily depends on the movement of free electrons. In aluminium alloys, this is complemented by lattice vibrations (phonons). Alloying elements can disrupt the lattice, scatter electrons and reduce thermal conductivity. Therefore, choosing elements that minimize lattice distortion is crucial for maintaining high thermal conductivity.

The Wiedemann-Franz law provides a valuable link between electrical and thermal conductivity, enabling predictions of thermal performance based on electrical resistivity. This relationship is instrumental in developing alloys with optimized thermal properties.

Microstructural Considerations

The microstructure of aluminium alloys, influenced by casting and heat treatment, significantly affects thermal conductivity. Instead of foreign atoms introducing lattice distortions, phases formed during casting enhance conductivity due to their unique structure. These phases act like a vacuum system, sucking in other elements from the lattice. Heat treatment can further refine the microstructure, impacting thermal performance.

Controlling microstructural features is vital for developing high-performance, sustainable aluminium alloys. Microporosity from a dendritic casting process is a barrier, significantly impacting heat transfer from one grain to another.

Conclusion

Therefore, low silicon (2–3%) and high iron (0.5–1%) alloys deliver the highest thermal properties and the lowest carbon footprint. And, Rheocasting is the only way to cast them to ensure a poros-free microstructure. Now you know how to get the best thermal management for power-hungry electronics. Schedule a Free Consultation Call to discuss your foundries situation down below.