Automotive Industry Adopts Aluminum Extrusion for Lightweighting

Imagine cars of the future that are more fuel-efficient, safer, and environmentally friendly - all achieved through innovative material selection. Aluminum extrusions are emerging as the key "secret weapon" to make this vision a reality.

Aluminum extrusions are created by forcing aluminum alloy through a die to form various complex shapes. Their applications in automobiles are remarkably diverse, appearing in structural components, crash beams, radiators, interior parts, and nearly every other area of vehicle design. What makes extruded aluminum so special that automakers are embracing it so enthusiastically?

• Lightweight Champion: With just one-third the density of steel, aluminum extrusions significantly reduce vehicle weight, improving fuel economy and reducing emissions.
• Cost Effective: While aluminum may seem expensive initially, extrusion allows multiple parts to be integrated into single components, reducing part counts and assembly steps while lowering overall costs.
• Rapid Development: Extrusion die production typically takes just two weeks, dramatically shortening vehicle development timelines.
• Thermal Management: Aluminum's excellent thermal conductivity makes it ideal for heat exchangers and battery cooling systems.
• Corrosion Resistance: Naturally corrosion-resistant aluminum often requires no additional protective coatings.
• Assembly Friendly: Easily formed and machined, aluminum extrusions accommodate various joining methods including welding and adhesive bonding.
• Structural Strength: Optimized cross-sections provide exceptional strength-to-weight ratios, meeting stringent automotive safety requirements.
• Superior Sealing: One-piece extrusion eliminates potential leak points at joints, particularly valuable for battery enclosures.

The extrusion process enables virtually unlimited geometric possibilities, allowing engineers to optimize shapes for specific performance requirements. Hollow sections reduce weight while improving energy absorption, while customized profiles enhance bending and torsional stiffness.

With numerous aluminum alloys available, automotive applications primarily utilize 6xxx series alloys. These magnesium-silicon alloys offer the best balance of strength, corrosion resistance, and extrudability.

For unique applications like micro-extruded tubes, alloys like 1100 (excellent formability) and 3003 (higher strength) may be specified for specialized components such as multi-port tubes and micro-channel heat exchangers.

An extrusion's microstructure - including grain size, morphology, and surface layer characteristics - critically impacts mechanical properties. These features depend on both alloy composition and processing parameters like extrusion temperature and quenching rate.

• Recrystallized Grains: The most common structure, with grain sizes typically between 25-400 microns. Controlling maximum grain size ensures proper formability.
• Fibrous Grains: Found in higher-strength alloys containing manganese, chromium, or zirconium, these improve mechanical properties but reduce ductility.
• Hybrid Structures: Often featuring recrystallized surface layers, where layer thickness must be carefully controlled to maintain optimal mechanical properties.

Environmental Product Declarations (EPDs) provide comprehensive data about aluminum extrusions' ecological impact, helping automakers make informed material selections.

• Reports multiple environmental metrics including global warming potential and resource depletion
• Complies with ISO standards and product category rules
• Five-year validity period for certified EPDs
• Industry-average EPDs available since 2016 (updated 2022)
• New tools enable customized, location-specific reporting
• Third-party certified by environmental consultants

Given the complex relationship between alloy selection, processing parameters, and final properties, close collaboration with experienced extrusion manufacturers is essential to achieve optimal performance and cost-effectiveness.

Aluminum extrusions are proving indispensable for automotive lightweighting, safety, and sustainability initiatives. Through informed material selection, microstructure control, and environmental awareness, automakers can fully leverage aluminum's advantages to create the next generation of high-performance vehicles.