Properties and Applications of 6061-T6 Aluminum Alloy

6061 (Unified Numbering System (UNS) designation A96061) is a precipitation-hardened aluminum alloy in which magnesium and silicon are the primary alloying elements. First introduced in 1935 under the name "Alloy 61S," it offers strong overall mechanical performance, excellent weldability, and is widely used in extrusion applications-second only to 6063 in popularity. Today, 6061 remains one of the most commonly utilized aluminum alloys for general-purpose applications.

It is typically supplied in pre-tempered variants such as 6061-O (annealed) and in heat-treated tempers including 6061-T6 (solution-treated and artificially aged) and 6061-T651 (solution-treated, stress-relieved by stretching, and artificially aged).

Chemical Composition of Aluminum 6061

Specification: BS EN 573-3:2009
Alloy: 6061

Properties of Aluminum 6061

Physical Properties

Mechanical Properties

Spec: BS EN 755-2:2008
Extrusions-up to 200 mm diameter/A/F, 5 mm wall thickness for tube and profiles

Mechanical Behavior by Temper

The mechanical properties of 6061 vary significantly with temper condition, while Young's Modulus remains approximately 69 GPa (10,000 ksi) across all tempers.

6061-O (Annealed)

In the O-temper (fully annealed), 6061 exhibits:

Maximum ultimate tensile strength ≤ 150 MPa (22 ksi)

Maximum yield strength ≤ 83 MPa (12 ksi) or 110 MPa (16 ksi)

Elongation of 10–18%

Annealing is typically performed at approximately 415°C for 2–3 hours.

6061-T4

In the T4 condition (solution-treated and naturally aged), mechanical properties include

Ultimate tensile strength ≥ 180 MPa (26 ksi) or 210 MPa (30 ksi)

Yield strength ≥ 110 MPa (16 ksi)

Elongation of 10–16%

6061-T6 / T651

The T6 temper delivers maximum precipitation hardening, thereby achieving the highest strength levels for 6061:

Ultimate tensile strength ≥ 290 MPa (42 ksi), typically 310 MPa (45 ksi)

Yield strength ≥ 240 MPa (35 ksi), typically 270 MPa (39 ksi)

Elongation: ≥ 8% (≤ 6.35 mm thickness) or ≥ 10% (thicker sections)

T651 provides similar mechanical performance but includes stress-relieving via stretching.
Additional properties:

Thermal conductivity at 25 °C: approx. 152 W/m·K

Fatigue limit: 97 MPa (14 ksi) for 500 million cycles in fully reversed loading

Because aluminum lacks a distinct "fatigue knee," the definition of infinite life varies. Fatigue performance also depends heavily on load conditions, stress gradients, and surface finishes.

Common Applications of 6061

6061 is widely used in structural, marine, transportation, and consumer applications, including

Aircraft structures such as wings and fuselages, particularly in homebuilt aircraft, where 6061's corrosion resistance and workability are advantageous versus 2024 (which requires Alclad coating)

Yacht and small boat construction

Automotive components, including the chassis of models such as the Audi A8 and Plymouth Prowler

Flashlight bodies

Food-grade and beverage aluminum cans

Scuba cylinders and other high-pressure gas containers (post-1995 production)

GNEE supplies 6061 in multiple tempers and product forms tailored to these and other application requirements.

Equivalent Materials

6061 Aluminum Alloy – International Equivalents