6061-T6 Aluminum vs. 6063-T6 Aluminum

6061-T6 and 6063-T6 are both part of the 6000 series of aluminum alloys, primarily composed of aluminum, magnesium, and silicon. However, they have different properties and are used in different applications.

6061-T6 and 6063-T6 are commonly used in various industries, including aerospace, construction, and manufacturing. While they share similarities, there are key differences in their composition and performance.

Property	6061-T6 Aluminum	6063-T6 Aluminum
Strength	Stronger, making it suitable for high-stress applications	Lower strength, suitable for applications with less stress
Extrusion Capability	Less suited for intricate extrusions	Better suited for extrusion, with smoother finishes and easier machinability
Applications	High-stress and structural components (aircraft, marine, automotive)	Architectural and decorative applications (window frames, railings)
Machinability	More difficult to machine due to higher strength	Easier to machine due to lower strength

6061-T6 Aluminum

Composition: 6061 aluminum is an alloy primarily made of aluminum, magnesium, and silicon. It is one of the most commonly used alloys for structural and aerospace applications.
Strength: 6061-T6 is known for its high strength and is considered one of the strongest heat-treated alloys.
Properties: It has excellent corrosion resistance, good workability, and is highly weldable. It also performs well in both anodized and painted finishes.
Applications: It is commonly used in aerospace (aircraft structures, fuselage, and wings), marine applications, automotive parts, and structural components for buildings and bridges.
Machinability: 6061 is more difficult to machine compared to 6063 due to its higher strength, but it is still considered highly machinable.

6063-T6 Aluminum

Composition: 6063 is also an aluminum alloy that contains magnesium and silicon but has a slightly different balance compared to 6061, which makes it more suited for applications requiring excellent surface finish and extrusion.
Strength: While 6063-T6 has a lower tensile strength compared to 6061-T6, it still has good strength for many applications.
Properties: Known for excellent corrosion resistance and a smoother finish, 6063 is particularly preferred in architectural applications. It is also easier to extrude and form into complex shapes compared to 6061.
Applications: It's widely used in architectural and decorative applications such as window frames, door frames, railings, and in some structural and general-purpose extrusions.
Machinability: 6063 is generally easier to machine than 6061 due to its lower strength, making it a better choice for applications requiring detailed, high-quality finishes.

How to Choose Between 6061-T6 and 6063-T6 Aluminum

If you need a material with high strength and durability, choose 6061-T6.
If you need a material that is easy to process, aesthetically pleasing, and with lower strength requirements, choose 6063-T6.

Properties	6061-T6	6063-T6
Main Composition	Magnesium (0.8% - 1.2%), Silicon (0.4% - 0.8%)	Silicon (0.2% - 0.6%), Magnesium (0.45% - 0.9%)
Strength	Higher tensile strength and yield strength	Lower tensile strength and yield strength
Weldability	Good	Good
Extrudability	Good	Excellent
Corrosion Resistance	Good	Good, but may be better under certain conditions
Appearance	Functionality is prioritized	Aesthetics are prioritized
Common Applications	Structural components (frames, chassis), aerospace, automotive, marine parts	Architectural applications (window frames, door frames), decorative applications, radiators
Cost	Generally higher	Generally lower

6061-T6 Aluminum vs. 6063-T6 Aluminum Alloy Composition

Element	6061-T6 Aluminum	6063-T6 Aluminum
Aluminum (Al), %	95.9 to 98.6	97.5 to 99.4
Chromium (Cr), %	0.040 to 0.35	0 to 0.1
Copper (Cu), %	0.15 to 0.4	0 to 0.1
Iron (Fe), %	0 to 0.7	0 to 0.35
Magnesium (Mg), %	0.8 to 1.2	0.45 to 0.9
Manganese (Mn), %	0 to 0.15	0 to 0.1
Silicon (Si), %	0.4 to 0.8	0.2 to 0.6
Titanium (Ti), %	0 to 0.15	0 to 0.1
Zinc (Zn), %	0 to 0.25	0 to 0.1
Residuals, %	0	0 to 0.15

6061-T6 Aluminum vs. 6063-T6 Aluminum Mechanical Properties

Property	6061-T6 Aluminum	6063-T6 Aluminum
Brinell Hardness	93	73
Elastic Modulus (Tensile), x 10⁶ psi	10	9.9
Elongation at Break (%)	10	11
Fatigue Strength, x 10³ psi	14	10
Poisson's Ratio	0.33	0.33
Shear Modulus, x 10⁶ psi	3.8	3.7
Shear Strength, x 10³ psi	30	22
Tensile Strength: Ultimate (UTS), x 10³ psi	45	35
Tensile Strength: Yield (Proof), x 10³ psi	39	30

6061-T6 Aluminum vs. 6063-T6 Aluminum Thermal Properties

Property	6061-T6 Aluminum	6063-T6 Aluminum
Latent Heat of Fusion, J/g	400	400
Maximum Temperature: Mechanical, °F	330	320
Melting Completion (Liquidus), °F	1190	1210
Melting Onset (Solidus), °F	1080	1140
Specific Heat Capacity, BTU/lb-°F	0.21	0.22
Thermal Conductivity, BTU/h-ft-°F	97	120
Thermal Expansion, µm/m-K	24	23

6061-T6 Aluminum vs. 6063-T6 Aluminum Electrical Properties

Property	6061-T6 Aluminum	6063-T6 Aluminum
Electrical Conductivity: Equal Volume, % IACS	43	53
Electrical Conductivity: Equal Weight (Specific), % IACS	140	180

Otherwise Unclassified Properties

Property	6061-T6 Aluminum	6063-T6 Aluminum
Base Metal Price, % relative	9.5	9.5
Calomel Potential, mV	-740	-740
Density, lb/ft³	170	170
Embodied Carbon, kg CO₂/kg material	8.3	8.3
Embodied Energy, x 10³ BTU/lb	66	66
Embodied Water, gal/lb	140	140

Common Calculations

Property	6061-T6 Aluminum	6063-T6 Aluminum
Resilience: Ultimate (Unit Rupture Work), MJ/m³	30	25
Resilience: Unit (Modulus of Resilience), kJ/m³	520	320
Stiffness to Weight: Axial, points	14	14
Stiffness to Weight: Bending, points	50	50
Strength to Weight: Axial, points	31	25
Strength to Weight: Bending, points	37	32
Thermal Diffusivity, mm²/s	68	82
Thermal Shock Resistance, points	14	11