Aluminum 6061 vs. 6063: Understanding the Difference
6061 and 6063 are two of the most commonly used aluminum alloys in the 6000 series, but they are typically selected for different reasons.
6061 aluminum generally offers higher strength and better machinability, while 6063 aluminum offers excellent extrudability, corrosion resistance and surface finish. For that reason, 6061 is frequently used for structural and machined components, while 6063 is especially common in architectural and general-purpose aluminum extrusions.
Both alloys contain magnesium and silicon and can be heat treated to improve their mechanical properties. However, differences in composition and temper affect their strength, fabrication characteristics, appearance and ideal applications.
If you're deciding between 6061 vs. 6063 aluminum, the right choice depends on whether your project prioritizes strength, machining, extrusion complexity, appearance, corrosion resistance or finishing.
6061 vs. 6063 Aluminum at a Glance
| Property | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| Strength | Higher | Moderate |
| Extrudability | Good | Excellent |
| Machinability | Very good | Good |
| Corrosion resistance | Very good | Excellent |
| Anodized appearance | Good | Excellent |
| Surface finish | Good | Excellent |
| Complex extrusion profiles | Good | Excellent |
| Structural applications | Excellent | Application dependent |
| Architectural applications | Good | Excellent |
| Common uses | Structural parts, frames, machined components | Extrusions, trim, channels, tubing, architectural profiles |
The simple answer: Choose 6061 when strength and machinability are the priority. Choose 6063 when extrudability, appearance and surface finish are more important.
What Is 6061 Aluminum?
6061 aluminum is a heat-treatable aluminum alloy containing magnesium and silicon as its primary alloying elements.
It is one of the most widely used aluminum alloys because it provides a strong balance of:
- Mechanical strength
- Corrosion resistance
- Machinability
- Weldability
- Fabrication capability
- Availability
6061 is frequently used when an aluminum component needs to carry greater loads or maintain higher mechanical strength while still providing the lightweight and corrosion-resistant benefits of aluminum.
Common applications for 6061 aluminum include:
- Structural frames
- Machine components
- Equipment
- Brackets
- Supports
- Automotive components
- Marine components
- Structural tubing
- Bars and rods
- Fabricated assemblies
6061 is also available in several tempers, with 6061-T6 being one of the most commonly encountered because of its higher strength.
What Is 6063 Aluminum?
6063 is also a magnesium-silicon aluminum alloy, but its composition and material characteristics make it particularly well suited for extrusion.
It is often referred to as an architectural aluminum alloy because it combines:
- Excellent extrudability
- Good corrosion resistance
- Smooth surface finish
- Excellent anodizing characteristics
- Good dimensional consistency
- Versatility for complex profile shapes
These characteristics make 6063 especially useful for aluminum profiles where appearance, shape complexity and finishing are important.
Common 6063 aluminum applications include:
- Architectural trim
- Channels
- Angles
- Tubing
- Frames
- Display systems
- Signage components
- Millwork profiles
- Furniture components
- Sliding systems
- Decorative profiles
- Custom aluminum extrusions
6063 is commonly supplied in T5 and T6 tempers, depending on the mechanical properties and manufacturing requirements of the finished profile.
6061 vs. 6063 Chemical Composition
6061 and 6063 are both part of the 6000-series aluminum family, meaning magnesium and silicon are their primary alloying elements.
However, their chemical compositions are not identical.
6061 generally contains higher levels of certain alloying elements that contribute to its increased strength. 6063 uses a composition optimized more heavily toward extrudability, finishing characteristics and corrosion resistance.
Typical composition ranges include:
| Element | 6061 Aluminum | 6063 Aluminum |
|---|---|---|
| Magnesium | 0.8–1.2% | 0.45–0.9% |
| Silicon | 0.4–0.8% | 0.2–0.6% |
| Copper | 0.15–0.4% | Up to 0.10% |
| Chromium | 0.04–0.35% | Up to 0.10% |
| Iron | Up to 0.70% | Up to 0.35% |
| Aluminum | Balance | Balance |
These composition differences help explain why 6061 typically provides greater strength while 6063 offers better extrusion and finishing characteristics.
Exact composition requirements are governed by the applicable alloy specification and should be verified when material certification or engineering requirements are involved.
6061 vs. 6063 Aluminum Properties
The difference between 6061 and 6063 becomes more apparent when comparing their mechanical and fabrication properties.
Strength
6061 is generally stronger than 6063 when comparing commonly used tempers.
Typical values illustrate the difference:
| Alloy & Temper | Typical Tensile Strength | Typical Yield Strength |
|---|---|---|
| 6061-T6 | Approx. 45 ksi | Approx. 40 ksi |
| 6063-T6 | Approx. 35 ksi | Approx. 31 ksi |
| 6063-T5 | Approx. 27 ksi | Approx. 21 ksi |
These are general reference values. Actual mechanical properties can vary depending on product form, thickness, temper and applicable specifications.
For applications where mechanical strength is a major design requirement, 6061 is often the preferred choice.
Which Is Stronger: 6061 or 6063 Aluminum?
In general, 6061 aluminum is stronger than 6063 aluminum.
This is one of the most important differences between the two alloys.
6061 is commonly used for structural components, brackets, frames and machined parts because it provides higher tensile and yield strength in commonly used tempers.
6063 still provides useful mechanical strength, but it is usually selected for a different combination of characteristics—particularly extrusion performance, appearance and finishing.
That does not mean 6063 is unsuitable for structural use. The correct alloy depends on the actual loads, profile geometry, temper, mounting method and engineering requirements of the application.
6061 vs. 6063 Extrudability
This is one area where 6063 has a major advantage.
6063 is one of the most widely used alloys for aluminum extrusion because it flows well through an extrusion die and can be formed into relatively intricate cross-sectional profiles.
This makes 6063 well suited for products such as:
- Channels
- Trim profiles
- Tubing
- Architectural shapes
- Tracks
- Framing components
- Display profiles
- Decorative extrusions
- Custom profiles
6061 can also be extruded, but it is generally more difficult to extrude than 6063, particularly when a profile incorporates thin walls, complex geometry or fine dimensional details.
For many extrusion applications, the decision therefore becomes a tradeoff:
6061 = greater strength
6063 = greater extrusion flexibility
Why Is 6063 Commonly Used for Aluminum Extrusions?
6063 aluminum combines several characteristics that are particularly valuable for extruded products.
It can accommodate a wide variety of profile geometries while producing a smooth surface that responds well to anodizing and other finishing processes.
This makes it particularly useful for aluminum products where the profile itself is a major part of the finished design.
6063 is widely used for architectural extrusions, trim, display components, millwork profiles, frames, tubing and other products where shape, appearance and consistency are important alongside mechanical performance.
6061 vs. 6063 Machinability
6061 is generally considered the better choice when extensive machining is required.
It machines cleanly and is commonly used for:
- CNC-machined components
- Drilled components
- Threaded parts
- Precision brackets
- Fixtures
- Equipment components
6063 can also be drilled, cut and machined, but machinability is usually not the primary reason for choosing it.
If a project involves significant machining after extrusion, 6061 may provide an advantage depending on the required profile and mechanical properties.
6061 vs. 6063 Corrosion Resistance
Both 6061 and 6063 provide good corrosion resistance.
6063 generally provides somewhat better natural corrosion resistance and is widely used in architectural and exposed applications.
However, alloy selection should not be based on exposure alone.
Environmental conditions, finish, installation method, contact with dissimilar metals and the specific application all influence corrosion performance.
Both alloys can also be anodized or otherwise finished to improve surface protection.
6061 vs. 6063 for Anodizing and Surface Finish
6063 is often preferred when appearance and anodized finish quality are important.
Its composition and extrusion characteristics allow it to produce smooth, consistent surfaces that respond particularly well to architectural anodizing.
This is one reason 6063 is commonly used for visible products such as:
- Architectural trim
- Frames
- Display components
- Signage systems
- Furniture components
- Decorative profiles
- Interior finishing products
6061 can also be anodized successfully, but 6063 is generally favored when cosmetic appearance is a primary consideration.
6061 vs. 6063 Weldability
Both 6061 and 6063 are considered weldable aluminum alloys.
However, welding can alter the mechanical properties of heat-treated aluminum around the weld's heat-affected zone.
This is especially important when using 6061 in structural applications where the mechanical properties of the welded assembly are important.
For engineered or load-bearing applications, welding procedures, filler material and post-weld mechanical properties should be considered as part of the overall design.
6061-T6 vs. 6063-T6
The alloy number is only part of an aluminum material designation.
The temper describes how the aluminum has been processed after forming to achieve specific mechanical characteristics.
Two commonly encountered materials are:
- 6061-T6
- 6063-T6
Both have been solution heat treated and artificially aged, but their resulting properties remain different because the base alloys have different compositions.
6061-T6 generally provides greater strength.
6063-T6 generally retains the extrusion and finishing advantages associated with 6063 while providing higher mechanical strength than softer 6063 tempers.
6063-T5 vs. 6063-T6
6063 is also commonly supplied in T5 temper.
The primary practical difference is strength.
6063-T6 generally provides higher mechanical strength than 6063-T5.
However, T5 is widely used for extruded products where its mechanical properties are sufficient for the intended application.
The correct temper depends on the profile, fabrication process, mechanical requirements and intended use.
6061 vs. 6063 Thermal Conductivity
Both alloys conduct heat effectively compared with many other engineering materials.
6063 generally has somewhat higher thermal conductivity than 6061, which can make it useful for certain thermal management and heat-transfer applications.
However, thermal conductivity should be considered alongside strength, extrusion geometry, temper and operating conditions when selecting material for a thermal application.
Common Applications for 6061 Aluminum
6061 is often chosen when mechanical performance is the primary requirement.
Typical applications include:
- Structural framing
- Equipment components
- Machine parts
- Brackets and supports
- Automotive components
- Marine components
- Structural tubing
- Bars
- Rods
- Fabricated assemblies
- CNC-machined components
Its combination of strength, machinability, weldability and corrosion resistance makes it one of the most versatile aluminum alloys available.
Common Applications for 6063 Aluminum
6063 is especially common in applications involving extruded profiles.
Typical uses include:
- Architectural trim
- Aluminum channels
- Angles
- Tubing
- Door and window components
- Display systems
- Signage
- Millwork profiles
- Furniture components
- Tracks
- Framing systems
- Decorative aluminum profiles
Its combination of extrudability, corrosion resistance and finish quality makes it particularly well suited for products where geometry and appearance matter as much as mechanical performance.
Should You Choose 6061 or 6063 Aluminum?
There is no single alloy that is better for every application.
Choose 6061 aluminum when your priorities include:
- Higher mechanical strength
- Structural performance
- Machinability
- Fabricated or machined components
- Greater load-bearing capability
Choose 6063 aluminum when your priorities include:
- Extrusion performance
- Complex profile shapes
- Smooth surface finish
- Architectural appearance
- Anodizing
- Corrosion resistance
- Decorative or visible components
For many extrusion applications, 6063 provides an excellent combination of performance, manufacturability and appearance.
For applications requiring greater structural strength or extensive machining, 6061 may be the better option.
Shop Aluminum Extrusions
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Our product selection includes aluminum channels, angles, tubes, bars, trim profiles, framing components, panel mounting systems and other specialty extrusions.
Use the button below to explore available aluminum profiles and find the right shape for your application.
Frequently Asked Questions About 6061 vs. 6063 Aluminum
What is the difference between 6061 and 6063 aluminum?
6061 generally provides higher strength and better machinability, while 6063 provides better extrudability, surface finish and anodizing characteristics. 6061 is commonly used for structural and machined components, while 6063 is widely used for architectural and general-purpose extrusions.
Which is stronger, 6061 or 6063 aluminum?
6061 is generally stronger than 6063 when comparing commonly used tempers. This makes 6061 particularly useful for structural components and applications where mechanical strength is a priority.
Is 6061 or 6063 better for aluminum extrusions?
Both alloys can be extruded, but 6063 has better extrudability and is particularly well suited for complex profile shapes, architectural products and applications requiring a high-quality surface finish.
Is 6061 or 6063 better for anodizing?
6063 is generally preferred when anodized appearance is a major consideration. Its surface characteristics make it particularly well suited for architectural and decorative finishes.
Is 6061 or 6063 better for machining?
6061 is generally preferred for machining. It is widely used for CNC-machined parts, brackets and other fabricated components.
Is 6063 aluminum strong?
Yes. 6063 provides useful mechanical strength and is used in a wide variety of commercial and architectural applications. However, 6061 generally provides greater strength when comparing common tempers.
Is 6061 aluminum corrosion resistant?
Yes. 6061 provides very good corrosion resistance and is used in both indoor and outdoor applications. Finishing processes such as anodizing can provide additional surface protection.
Can 6061 and 6063 aluminum be welded?
Yes. Both alloys are considered weldable. Welding can affect mechanical properties around the heat-affected zone, so structural applications should account for the properties of the completed welded assembly.
What is the difference between 6061-T6 and 6063-T6?
6061-T6 generally offers greater mechanical strength, while 6063-T6 offers better extrudability and surface-finishing characteristics. The correct material depends on whether the application prioritizes strength, profile geometry, appearance or other performance requirements.
