Aluminium Alloy Selection Guide: A380 vs ADC12 vs A356 for High-Performance Applications

Selecting the optimal aluminium alloy represents a balance between manufacturing castability, mechanical yield requirements, corrosion exposure, and post-machining operations. Here is a definitive technical comparison of the three most specified alloys in precision manufacturing.

A380: The North American Workhorse

A380 (ANSI) has long been the most common aluminium die-casting alloy. With roughly 8.5% Silicon and 3.5% Copper, it balances fluidity with high dimensional stability.

• **Strengths:** Excellent pressure tightness, easy to cast in intricate geometries, good mechanical properties under room temperature.
• **Watchouts:** The 3.5% copper content reduces natural corrosion resistance in marine or salt-spray environments. Anodizing yields a dark brownish-grey finish rather than decorative clear.

ADC12: The Japanese & Global Standard for Electronics & EV

ADC12 (JIS H5302) closely resembles A383. Its higher Silicon content (9.5–11.5%) gives it superior fluid flow, making it the preferred choice for thin-walled electronics enclosures, 5G heatsinks, and complex automotive brackets.

• **Strengths:** Outstanding thin-wall castability, lower die wear, excellent dimensional stability.
• **Watchouts:** Similar to A380, copper presence necessitates powder coating or e-coating for extreme environmental durability.

A356: The High-Integrity Structural Alloy

A356 contains 7% Silicon and 0.35% Magnesium with virtually zero copper (< 0.2%). It is the undisputed champion when high elongation (ductility) and impact toughness are mandatory.

• **Strengths:** Fully responsive to T6 solutionizing and artificial aging. Achieves elongation of 6% to 12% (compared to 1.5–3.5% in standard die casting). Outstanding corrosion resistance and weldability.
• **Manufacturing Process:** Cast via Low Pressure Die Casting (LPDC), Gravity Die Casting, or high-end Vacuum HPDC.