6061 vs. 7075 vs. 2024 vs. 5052: How to Choose the Right Aluminum Alloy

“Just make it out of aluminum” hides a real decision. 6061, 7075, 2024, and 5052 behave so differently that swapping one for another can double your cost, halve your fatigue life, or make a part impossible to weld. This guide sorts the four workhorse aluminum alloys by what actually drives the choice — strength, corrosion, weldability, and formability — so you can spec the right one the first time.

The Aluminum Naming System in One Minute

Wrought aluminum alloys use a four-digit series where the first digit is the main alloying element: 2xxx (copper), 5xxx (magnesium), 6xxx (magnesium + silicon), and 7xxx (zinc). The temper suffix — -T6, -T651, -H32 — tells you how it was hardened. That suffix matters as much as the alloy: 6061-O is dead soft, while 6061-T6 is a structural material. Always spec the temper.

The Four You Will Actually Use

6061 — the default

6061-T6 is the aluminum you reach for when nothing pushes you elsewhere: good strength (~40 ksi yield), excellent corrosion resistance, weldable, machinable, and cheap. Structural extrusions, brackets, plates, frames, enclosures. If a part does not have a special demand, it is probably 6061.

7075 — when you need strength-to-weight

7075-T6 is the strong one — yield around 73 ksi, rivaling mild steel at a third of the weight. It is the aerospace and high-stress-bracket choice. The trade-offs are real: it is essentially not weldable, its corrosion resistance is poorer (often used clad or anodized), and it costs more. Use it where the strength earns its keep, not as a default.

2024 — fatigue and aircraft skins

2024-T3 trades some ultimate strength for excellent fatigue resistance and damage tolerance, which is why it clads aircraft fuselages. The copper content that gives it strength also makes it corrode readily (hence “Alclad” versions) and non-weldable. Choose it for cyclically loaded structure, not general fabrication.

5052 — sheet metal and marine

5052-H32 is the formability and corrosion champion. It bends without cracking, takes a tight radius, and shrugs off salt water — ideal for enclosures, fuel tanks, marine parts, and anything that starts as sheet. It is weaker than 6061 and does not heat-treat to higher strength, but for formed sheet it is hard to beat.

Side-by-Side

Two Traps Worth Naming

Welding destroys temper. Even on weldable 6061, the heat-affected zone drops toward the annealed (-O) strength — you lose roughly a third of the yield locally unless the part is re-heat-treated. Design welded aluminum joints around the weakened HAZ, not the parent T6 number.

Aluminum in contact with other metals corrodes galvanically. Bolt aluminum to stainless or steel in a wet environment and the aluminum becomes the sacrificial anode. Check the pairing before you assemble — our Galvanic Compatibility Checker flags the risky combinations and suggests isolation.

Temper Matters as Much as the Alloy Number

Two parts stamped “6061” can differ by 4× in strength depending on temper. -O is annealed and soft, meant for forming. -T4 is naturally aged — partway hardened, more ductile. -T6 is fully solution-treated and artificially aged for maximum strength, and it is what “structural 6061” almost always means. On plate you will also see -T651, which is -T6 that was stress-relieved by stretching so it stays flat after machining — specify it for anything you will mill from thick stock, or the part will bow as you remove material.

Cost, Machining, and Finishing

On raw material cost the rough order is 5052 ≈ 6061 < 2024 < 7075, and the high-strength alloys carry a machining and availability penalty on top of that. All four machine well compared with steel, but 6061 and 7075 chip cleanest; 5052 is gummy and better suited to forming than heavy milling. For finishing, 6061 and 5052 anodize to a clean, consistent color, while the copper in 2024 and the zinc in 7075 can give patchy or off-color anodized finishes — worth knowing if the part is cosmetic. When in doubt, hard-anodizing adds wear resistance to any of them but grows the part a few tenths of a mil per surface, which matters on a tight fit.

Look Up the Numbers

For full mechanical properties, tempers, and machinability side by side, use the Aluminum Alloy Comparison tool. If your part might be better in a polymer, compare against engineering plastics, and browse the rest of the Materials & Process reference set.