Which alloy number corresponds to a high-strength aluminum alloy that uses zinc as an alloying component?

• A. 2024-T
• B. 6061-T6
• C. 7075
• D. 7050-T7451

Answer: (C)

Zinc as the main alloying element is what defines the high-strength 7xxx series aluminum alloys. Among these, 7075 is the classic example, using zinc as the primary alloying component along with magnesium and a little copper. This combination delivers very high strength and good fatigue performance, which is why 7075 is widely used in aerospace structural parts. The tempering (for example, T6) further increases strength through precipitation hardening. Other options don’t fit as the primary zinc-containing high-strength alloy: 2024 relies mainly on copper, 6061 on magnesium and silicon, and while 7050 is also a strong 7xxx alloy and optimized for corrosion resistance, the standout zinc-containing high-strength alloy most commonly associated with aircraft use is 7075.