6061-T6 vs 6063-T5
6061-T6 and 6063-T5 are both 6000-series magnesium-silicon aluminum alloys sharing 2.7 g/cm³ density, but they serve different roles. 6061 is the all-round structural workhorse with higher strength, while 6063 is an architectural extrusion alloy optimized for smooth finishes and complex thin-wall profiles. Engineers weigh them when balancing load-bearing strength against extrudability, anodized appearance and surface quality.
The verdict
Choose 6061-T6 for structural and machined parts needing strength — at 276 MPa yield it nearly doubles 6063-T5's 145 MPa. Choose 6063-T5 for architectural extrusions, trim and complex thin-wall profiles where surface finish, intricate die shapes and good anodizing matter more than load capacity; it extrudes more easily and conducts heat better.
Side-by-side data
| Property | 6061-T6 | 6063-T5 |
|---|---|---|
| Category | Aluminum | Aluminum |
| Density (g/cm³) | 2.7 | 2.7 |
| Tensile strength (MPa) | 310 | 186 |
| Yield strength (MPa) | 276 | 145 |
| Elongation (%) | 12 | 12 |
| Hardness | 95 HB | 60 HB |
| Max service temp (°C) | 170 | 170 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 167 | 200 |
| Typically used for | All-round structural & machined parts — the default aluminum | Architectural & complex extrusions |
Which should you choose?
Choose 6061-T6 when…
- The part is structural or load-bearing — 276 MPa yield handles real stress
- It will be CNC machined (6061 is the default machinable aluminum)
- You need a versatile alloy for sheet, plate, bar and extrusion
- Welding is required (6061 is readily weldable)
- General-purpose strength and availability outweigh finish refinement
- The design mixes machined and extruded features in one part
Choose 6063-T5 when…
- The part is an architectural extrusion — window frames, railings, trim
- Complex, thin-wall or intricate die profiles are required
- A smooth surface finish and high-quality anodizing matter
- Loads are light and appearance/geometry drive the design
- Better thermal conductivity is useful (200 vs 167 W/m·K), e.g. heat-sink profiles
- Easy extrudability and tight, detailed cross-sections are priorities
Key differences that matter
- Both are 6000-series Al-Mg-Si alloys; 6061 is structural, 6063 is architectural-extrusion focused
- 6061-T6 is much stronger: 310/276 MPa tensile/yield vs 6063-T5's 186/145 MPa
- 6063 extrudes more easily into complex thin-wall profiles with smoother surfaces
- 6063 conducts heat better (200 vs 167 W/m·K), useful for heat-sink extrusions
- Both share 2.7 g/cm³ density and similar good corrosion resistance
- 6061 is the more machinable, more versatile general-purpose choice (sheet/plate/bar/extrusion)
- 6063 anodizes to a finer cosmetic finish; 6061 is fine functionally but less refined cosmetically
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Open the Material SelectorGet a Quote →Frequently asked questions
Is 6061 stronger than 6063?
Yes, clearly. 6061-T6 reaches about 310 MPa tensile and 276 MPa yield, while 6063-T5 sits near 186 MPa tensile and 145 MPa yield — roughly half. For any structural or load-bearing part 6061 is the right choice; 6063 is intended for architectural profiles where strength is secondary to shape and finish.
Why is 6063 used for extrusions?
6063 has lower alloy content that makes it more fluid through extrusion dies, so it forms complex, thin-walled and intricate cross-sections with smoother surfaces than 6061. Combined with excellent anodizing response, that makes it the standard for window frames, railings and decorative trim where geometry and finish lead.
Which anodizes and finishes better?
6063. Its cleaner chemistry gives a brighter, more uniform anodized surface, which is why it dominates visible architectural work. 6061 anodizes acceptably but tends to look slightly duller and less even, so for cosmetic parts 6063 is preferred while 6061 is chosen for structural function.
Which conducts heat better?
6063, at about 200 W/m·K versus 6061's 167 W/m·K. That higher thermal conductivity, combined with easy extrusion of finned profiles, makes 6063 a common choice for heat sinks and thermal-management extrusions. 6061 still conducts well but trades a little conductivity for higher strength.
Are both weldable and corrosion resistant?
Yes. Both are 6000-series alloys with good corrosion resistance and both can be welded, though heat-treated tempers lose some strength in the weld zone. They share the same 2.7 g/cm³ density; the practical decision is strength and machinability (6061) versus extrudability and finish (6063).
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.