The table below expresses the constituting elements for the two aluminum alloys, showing their quantities.
| Element | Aluminum 6061 | Aluminum 6063 |
| Aluminum | 97.9 % | 98.5 % |
| Magnesium | 1.0 % | 0.45 % |
| Silicon | 0.6 % | 0.2 % |
| Copper | 0.15 to 0.4 % | 0 to 0.10 % |
| Zinc | 0 to 0.25 % | 0 to 0.10 % |
| Manganese | 0 to 0.15 % | 0 to 0.10 % |
| Iron | 0 to 0.7 % | 0 to 0.35 % |
| Titanium | 0 to 0.15 % | 0 to 0.10 % |
| Chromium | 0.04 to 0.35 % | 0 to 0.10 % |
Observing this table, it is clear that the allies contain similar elements, though the amounts may vary. In fact, the trace elements don't have a distinct quantity, so some may not even be present.
However, this slight variation plays a significant role in the properties of the metals. For example, aluminum 6061 contain more magnesium and silicon, which makes the alloy more difficult to extrude, requiring higher temperatures.
2. Corrosion Resistance
Aluminum forms a thin oxide layer upon exposure to oxygen or other oxidative conditions, protecting the metal from corrosion. The alloys retain this property – aluminum 6061 and aluminum 6063 have good corrosion resistance.
However, the 6061 variant has a slightly increased silicon and magnesium content, increasing its chances of corrosion. Therefore, aluminum 6063 has more excellent corrosion resistance than the 6061 alloys.
In addition, the variation in their resistance to corrosion is almost minimal. Therefore, the metals are suitable for similar applications. The corrosion resistance may also depend on the environment the aluminum product is exposed to.
3. Durability
Generally, both metals are highly durable, showing suitable strength that makes them ideal for vast applications. However, remember that aluminum 6061 is slightly less corrosion-resistant than the 6063 variant; we can infer that the latter is more durable.
Also, aluminum 6061 has a slightly higher tensile strength, fatigue strength, and yield strength. It may be difficult to compare their durability. As we said earlier, the environment where the metals are used may also play a crucial role in their durability.
4. Weight
Aluminum is a lightweight metal. This feature remains consistent in all its alloys. Standard aluminum has a density of 2.70 g/cm³ (0.0975 lb/in³). Aluminum 6061 maintains this density, while aluminum 6063 is slightly less dense at 2.69 g/cm³ (0.0972 lb/in³).
The difference in density may seem non-significant. However, the values show that AL 6061 is slightly heavier than 6063 and may prove more critical in large-sized products.
5. Machinability
Observing the machining properties of aluminum 6061 vs 6063, both alloys have excellent machining properties. The strength and hardness of either alloy are comparable, which accounts for their machinability.
Also, their good surface finish, smooth silvery appearance, and good chip formation make them good candidates for CNC machining operations, including drilling, turning, and milling.
However, machinists prefer to use the 6061 aluminum grade in machining and reserve the 6063 grade for extrusion purposes.
6. Weldability
Generally, aluminum has good weldability, including its various alloys. However, comparing aluminum 6061 to aluminum 6063, the latter has better weldability.
The slightly higher magnesium content in Al 6061 increases its porosity and tendency to crack. Also, 6063 aluminum is more responsive to heat. All these features give 6063 better weldabilities than their counterparts.
