What are common aluminum alloys and their uses?
6061: Aerospace and bicycle frames (magnesium/silicon).
2024: Aircraft structures (copper/magnesium).
5052: Marine equipment (magnesium/chromium).
7075: High-stress parts like gears (zinc/magnesium).
Alloys enhance strength, corrosion resistance, or machinability.
How does adding silicon improve cast aluminum?
Silicon lowers melting points and reduces shrinkage during casting. It improves fluidity for complex molds. Hypereutectic alloys (16-18% silicon) resist wear in engine blocks. Silicon also boosts thermal conductivity for cookware.
Why is magnesium a key alloying element?
Magnesium increases strength without sacrificing corrosion resistance. It improves weldability in marine-grade alloys (e.g., 5083). Magnesium-aluminum alloys are used in ladders and automotive parts.
What makes aluminum-lithium alloys unique?
Lithium reduces density by 3% and increases stiffness by 5%. These alloys are used in aerospace (e.g., Airbus A380). They resist fatigue and outperform traditional alloys. Production costs are higher due to lithium's reactivity.
How do heat treatments strengthen aluminum alloys?
Solution heat treatment dissolves alloying elements, followed by quenching. Aging (natural or artificial) precipitates fine particles that block dislocations. T6 tempering maximizes hardness. Processes vary by alloy (e.g., 6061-T6 vs. 7075-T651).
