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Should I use 6061 or 6063 aluminum?
Use 6061-T6 for machined and load-bearing parts: it is about two-thirds stronger, 45 ksi (310 MPa) tensile versus 27 ksi (186 MPa) for 6063-T5, and it machines cleaner. Use 6063 for custom extruded profiles, heat sinks and visible trim. It extrudes thin, complex walls faster and anodizes to a more uniform color and gloss.
Aluminum 6061-T6
Aluminum 6063-T5
By the numbers
Priced on the same representative part: plate, cnc machining, 50 pcs.
Tensile strengthMPa
6061-T6
310
6063-T5
186
Yield strengthMPa
6061-T6
276
6063-T5
145
Densityg/cm³
6061-T6
2.7
6063-T5
2.7
Max service temp°C
6061-T6
150
6063-T5
150
Elongation%
6061-T6
12
6063-T5
12
Raw material cost$/kg
6061-T6
7
6063-T5
5.5
Which should you pick?
Pick 6061-T6 when
- The part is machined from bar or plate
- It carries structural or highly stressed loads
- Tapped holes and fine features need clean, low-burr machining
- You need a standard bar or plate size off the shelf
Pick 6063-T5 when
- The shape is a custom extruded profile, rail or frame
- Anodized color must match across many visible parts
- The part is an extruded heat sink with thin, closely spaced fins
- The profile needs walls of 0.040–0.060 in (1.0–1.5 mm)
Key differences
| 6061-T6 | 6063-T5 | |
|---|---|---|
| Primary product form | Machining bar, plate, sheet and tube | Extrusions; bar and plate are less common |
| Extrusion capability | Extrudes, but slower and in simpler, heavier shapes | Complex thin-wall profiles at high press speed |
| Anodize finish | Clean clear and dyed colors | Most uniform color and gloss of the common alloys |
| Machining behavior | Good chip control; finishes to 32 µin Ra (0.8 µm) | Soft and gummy; expect burrs and built-up edge |
| Temper | T6: solution heat-treated, quenched and aged | T5: aged straight off the press; 6063-T6 reaches about 35 ksi (241 MPa) |
| Typical tolerance | Machined, ±0.005 in (±0.13 mm) standard | Extruded to ANSI H35.2, looser; machine critical features |
| Tooling | None when machined from stock | Custom extrusion die, typically $1,000–$5,000 |
Questions
Is 6063 aluminum weaker than 6061?
Yes. 6063-T5 runs about 27 ksi (186 MPa) tensile and 21 ksi (145 MPa) yield, roughly 60% of 6061-T6. 6063-T6 closes some of the gap at about 35 ksi (241 MPa). For highly stressed parts, use 6061-T6.
Which is better for heat sinks, 6061 or 6063?
6063 for extruded heat sinks. It conducts about 209 W/m·K versus 167 W/m·K for 6061 and extrudes the thin, closely spaced fins heat sinks need, with fin height-to-gap ratios up to about 10:1. Machined heat sinks and cold plates are usually 6061.
Can 6063 be machined?
Yes, but it is softer and gummier than 6061, so expect burrs and built-up edge. Sharp, high-rake tools and a deburr step help. Extrusions are often machined at critical holes and faces; parts machined mostly from solid should be 6061.
Which anodizes better, 6061 or 6063?
6063 gives the most uniform color of the common alloys in clear and dyed Type II anodize, which is why architectural and consumer trim uses it. 6061 anodizes well too; anodize matching parts in the same alloy and lot.
Try both on your part.
The builder prices the same geometry in every suitable process and material, with DFM for each.