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6061-T6 aluminum

A6061
Physical Properties
Density (ρ) 2.70 g/cm3
Mechanical Properties
Young's modulus (E) 68.9 GPa (9,990 ksi)
Tensile strengtht) 124–290 MPa (18.0–42.1 ksi)
Elongation (ε) at break 12–25%
Poisson's ratio (ν) 0.33
Thermal Properties
Melting temperature (Tm) 585 °C (1,085 °F)
Thermal conductivity (k) 151–202 W/(m·K)
Linear thermal expansion coefficient (α) 2.32×10−5 K−1
Specific heat capacity (c) 897 J/(kg·K)
Electrical Properties
Volume resistivity (ρ) 32.5–39.2 nOhm·m

6061 is a precipitation-hardened aluminium alloy, containing magnesium and silicon as its major alloying elements. Originally called "Alloy 61S", it was developed in 1935. It has good mechanical properties, exhibits good weldability, and is very commonly extruded (second in popularity only to 6063). It is one of the most common alloys of aluminium for general-purpose use.

It is commonly available in pre-tempered grades such as 6061-O (annealed), tempered grades such as 6061-T6 (solutionized and artificially aged) and 6061-T651 (solutionized, stress-relieved stretched and artificially aged).

The alloy composition of 6061 is:

The mechanical properties of 6061 depend greatly on the temper, or heat treatment, of the material.Young's Modulus is 69 GPa (10,000 ksi) regardless of temper.

Annealed 6061 (6061-O temper) has maximum tensile strength no more than 120 MPa (18,000 psi), and maximum yield strength no more than 55 MPa (8,000 psi). The material has elongation (stretch before ultimate failure) of 25–30%.

T4 temper 6061 has an ultimate tensile strength of at least 210 MPa (30,000 psi) and yield strength of at least 110 MPa (16,000 psi). It has elongation of 16%.

T6 temper 6061 has an ultimate tensile strength of at least 290 MPa (42,000 psi) and yield strength of at least 240 MPa (35,000 psi). More typical values are 310 MPa (45 ksi) and 270 MPa (39 ksi), respectively. In thicknesses of 6.35 mm (0.250 in) or less, it has elongation of 8% or more; in thicker sections, it has elongation of 10%. T651 temper has similar mechanical properties. The typical value for thermal conductivity for 6061-T6 at 25 °C (77 °F) is around 152 W/m K. A material data sheet defines the fatigue limit under cyclic load as 97 MPa (14,000 psi) for 500,000,000 completely reversed cycles using a standard RR Moore test machine and specimen. Note that aluminium does not exhibit a well defined "knee" on its S-n graph, so there is some debate as to how many cycles equates to "infinite life". Also note the actual value of fatigue limit for an application can be dramatically affected by the conventional de-rating factors of loading, gradient, and surface finish.


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