AA (Aluminium Alloy) 6061-T6 is an aluminium alloy which is precipitation-hardened. Precipitation hardening is a heat treatment technique which increases the yield strength of the malleable materials, including most alloys of aluminium. AA 6061-T6 contains magnesium and silicon as the alloying elements which occupy a major stake in its making.
AA 6063-T5 is also an aluminium alloy having the same alloying elements of magnesium and silicon. So the to find the key difference between the two, we must first take a look at the chemical composition of both.
The Chemical Composition for 6061-T6 is as follows:
Magnesium minimum 0.8%, maximum 1.2%
Zinc no minimum, maximum 0.25%
Titanium no minimum, maximum 0.15%
Silicon minimum 0.4%, maximum 0.8% by weight
Iron no minimum, maximum 0.7%
Copper minimum 0.15%, maximum 0.4%
Manganese no minimum, maximum 0.15%
Other elements no more than 0.05% each, 0.15% total
Remainder aluminium (95.85–98.56%)
The Chemical Composition for 6063-T5 is as follows:
Silicon minimum 0.2%, maximum 0.6% by weight
Iron no minimum, maximum 0.35%
Copper no minimum, maximum 0.10%
Manganese no minimum, maximum 0.10%
Magnesium minimum 0.45%, maximum 0.9%
Chromium no minimum, maximum 0.10%
Zinc no minimum, maximum 0.10%
Titanium no minimum, maximum 0.10%
Other elements no more than 0.05% each, 0.15% total)
To further differentiate between the two, we now take a look at the mechanical properties.
AA (Aluminium Alloy) 6061-T6 possesses very high tensile strength of at least 290 MPa or 42,000 psi. It also possesses the yield strength of at least 240 MPa or 35,000 psi. Normal tensile strength values are 310 MPa or 45 ksi and 270 MPa or 39 ksi. In case of thicknesses of 6.35 mm or 0.250 inches or less, AA 6061-T6has elongation of 8% or more, while in the thicker sections, it can have an elongation of 10%.
AA 6063-T5 possesses high tensile strength of at least 140 MPa or 20,000 psi. In case of thicknesses up to 13 millimetres or 0.5 inches, and 130 MPa or 19,000 psi from 13 mm or 0.5 inches thick. The yield strength of at least 97 MPa or 14,000 psi up to 13 millimetres or 0.5 inches and 90 MPa or 13,000 psi from 13 to 25 mm or 0.5 to 1 inches. It has elongation of 8%.
Now, that we have learnt the mechanical properties and chemical composition, it’s time to take a look into the uses or applications of both of these alloys.
Aluminium Alloy 6061-T6 possesses a very high tensile strength and good weldability. Hence it is used in:
Fly fishing reels.
The secondary chambers and baffle systems in firearm sound suppressors
The upper and lower receivers of many non mil-spec AR-15 rifle variants.
Many parts for remote controlled model aircraft, notably helicopter rotor components.
Docks and gangways are constructed with 6061-T6 extrusions.
Bicycle frames and components.
The Pioneer plaque.
Material used in some ultra-high vacuum (UHV) chambers)