6061 aluminium alloy ( Unified Numbering System (UNS) designation A96061) is a precipitation-hardened

aluminium alloy An aluminium alloy ( UK/IUPAC) or aluminum alloy ( NA; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There ...

, containing

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

and

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

as its major

alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...

ing elements. Originally called "Alloy 61S", it was developed in 1935. It has good mechanical properties, exhibits good

weldability The weldability, also known as joinability,. of a material refers to its ability to be welded. Many metals and thermoplastics can be welded, but some are easier to weld than others (see Rheological weldability). A material's weldability is used t ...

, and is very commonly

extruded Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex ...

(second in popularity only to 6063). It is one of the most common alloys of

aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

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).

Chemical composition

6061 Aluminium alloy composition by mass:

Properties

The mechanical properties of 6061 greatly depend on the temper, or heat treatment, of the material.Alcoa 6061 data sheet
(pdf), accessed October 13, 2006

Young's Modulus Young's modulus (or the Young modulus) is a mechanical property of solid materials that measures the tensile or compressive stiffness when the force is applied lengthwise. It is the modulus of elasticity for tension or axial compression. Youn ...

is regardless of temper.

6061-O

Annealed 6061 (6061-O temper) has maximum

ultimate tensile strength Ultimate tensile strength (also called UTS, tensile strength, TS, ultimate strength or F_\text in notation) is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials, the ultimate t ...

no more than ,ASTM B209ASTM B221 and maximum

yield strength In materials science and engineering, the yield point is the point on a stress–strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and w ...

no more than or . The material has elongation (stretch before ultimate failure) of 10–18%. To obtain the annealed condition, the alloy is typically heat soaked at 415 °C for 2-3 hours.

6061-T4

T4 temper 6061 has an

of at least or and yield strength of at least . It has elongation of 10-16%.

6061-T6

T6 temper 6061 has been treated to provide the maximum precipitation hardening (and therefore maximum yield strength) for a 6061 aluminium alloy. It has an ultimate tensile strength of at least and yield strength of at least . More typical values are and , respectively. This can exceed the yield strength of certain types of

stainless steel Stainless steel, also known as inox, corrosion-resistant steel (CRES), or rustless steel, is an iron-based alloy that contains chromium, making it resistant to rust and corrosion. Stainless steel's resistance to corrosion comes from its chromi ...

. In thicknesses of 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 is around 152 W/m K. The

fatigue limit The fatigue limit or endurance limit is the stress (mechanics), stress level below which an infinite number of loading cycles can be applied to a material without causing fatigue (material), fatigue failure. Some metals such as ferrous alloys and ...

under cyclic load is 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 curve, 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.

Microstructure

Different aluminium heat treatments control the size and dispersion of precipitates in the material. Grain boundary sizes also change, but do not have as important of an impact on strength as the precipitates. Grain sizes can change orders of magnitude based upon stress and can have grains as small as a few hundred nanometres, but are typically a few micrometres to hundreds of micrometres in diameter. Iron, manganese, and chromium secondary phases (, ) often form as inclusions in the material. 6061 Aluminum Grain Boundaries

Grain sizes in aluminium alloys are heavily dependent upon the processing techniques and heat treatment. Different cross-sections of material which has been stressed can cause order of magnitude differences in grain size. Some specially processed aluminium alloys have grain diameters which are hundreds of nanometres, but most range from a few micrometres to hundreds of micrometres.

Uses

6061 is commonly used for the following: *construction of

aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...

structures, such as

wing A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...

s and

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

s, more commonly in

homebuilt aircraft Homebuilt aircraft, also known as amateur-built aircraft or kit planes, are constructed by persons for whom this is not a professional activity. These aircraft may be constructed from "scratch", from plans, or from assembly kits.Armstrong, Kenn ...

than commercial or military aircraft.Aluminum Information at aircraftspruce.com
accessed October 13, 2006 2024 alloy is somewhat stronger, but 6061 is more easily worked and remains resistant to corrosion even when the surface is abraded. This is not the case for 2024, which is usually used with a thin

Alclad Alclad is a corrosion-resistant aluminium sheet formed from high-purity aluminium surface layers metallurgically bonded (rolled onto) to high-strength aluminium alloy core material. It has a melting point of about . Alclad is a trademark of Alcoa ...

coating for corrosion resistance. *

yacht A yacht () is a sail- or marine propulsion, motor-propelled watercraft made for pleasure, cruising, or racing. There is no standard definition, though the term generally applies to vessels with a cabin intended for overnight use. To be termed a ...

construction, including small utility

boat A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size or capacity, its shape, or its ability to carry boats. Small boats are typically used on inland waterways s ...

s.''Boatbuilding with Aluminum'', Stephen F. Pollard, 1993, *automotive parts, such as the chassis of the

Audi A8 The Audi A8 is a full-size luxury vehicle, luxury sedan (car), sedan manufactured and marketed by the German automaker Audi since 1994. Succeeding the Audi V8, and now in its fourth generation, the A8 has been offered with either front-wheel dri ...

and the

Plymouth Prowler The Plymouth Prowler, later the Chrysler Prowler, is a two-door, two passenger sports car, manufactured and marketed by DaimlerChrysler for model years 1997-2002 — widely known for it's hand-crafted aluminum bodywork and its Retro style, ...

. *flashlights * Scuba tanks and other high pressure gas storage cylinders (post 1995) 6061-T6 is used for: *

bicycle frame A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles: a main triangle ...

s and components *middle to high-end recurve risers *many

fly fishing Fly fishing is an angling technique that uses an ultra-lightweight lure called an artificial fly, which typically mimics small invertebrates such as flying and aquatic insects to attract and catch fish. Because the mass of the fly lure is in ...

reels. *the Pioneer plaque *the secondary chambers and baffle systems in firearm sound

suppressor A silencer, also known as a sound suppressor, suppressor, or sound moderator, is a gun barrel#Muzzle, muzzle device that suppresses the muzzle blast, blast created when a gun (firearm or airgun) is discharged, thereby reducing the sound inten ...

s (primarily pistol suppressors for reduced weight and improved mechanical functionality), while the primary expansion chambers usually require 17-4PH or 303

titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

. *the upper and lower receivers of many non mil-spec AR-15 rifle variants. *many aluminium docks and gangways, welded into place. *material used in some

ultra-high vacuum Ultra-high vacuum (often spelled ultrahigh in American English, UHV) is the vacuum regime characterised by pressures lower than about . UHV conditions are created by pumping the gas out of a UHV chamber. At these low pressures the mean free path of ...

(UHV) chambers *many parts for remote controlled

model aircraft A model aircraft is a physical model of an existing or imagined aircraft, and is built typically for display, research, or amusement. Model aircraft are divided into two basic groups: flying and non-flying. Non-flying models are also termed s ...

, notably

helicopter rotor On a helicopter, the main rotor or rotor system is the combination of several rotary wings (rotor blades) with a control system, that generates the aerodynamic lift (force), lift force that supports the weight of the helicopter, and the thrust ...

components. *large

amateur radio Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emer ...

antennas. *fire department rescue ladders

Welding

6061 is highly weldable, for example using

tungsten inert gas welding Gas tungsten arc welding (GTAW, also known as tungsten inert gas welding or TIG, tungsten argon gas welding or TAG, and heliarc welding when helium is used) is an arc welding process that uses a non-consumable tungsten electrode to produce the ...

(TIG) or metal inert gas welding (MIG). Typically, after welding, the properties near the weld are those of 6061-T4, a loss of strength of around 40%. The material can be re-heat-treated to restore near -T6 temper for the whole piece. After welding, the material can naturally age and restore some of its strength as well. Most strength is recovered in the first few days to a few weeks. Nevertheless, the Aluminum Design Manual (Aluminum Association) recommends the design strength of the material adjacent to the weld to be taken as 165 MPa/24000 PSI without proper heat treatment after the welding. Typical filler material is 4043 or 5356.

Extrusions

6061 is an alloy used in the production of

extrusion Extrusion is a process used to create objects of a fixed cross section (geometry), cross-sectional profile by pushing material through a Die (manufacturing), die of the desired cross-section. Its two main advantages over other manufacturing pro ...

s—long constant–cross-section structural shapes produced by pushing metal through a shaped die. Cold and Hot Stamping 6061 sheet in the T4 condition can be formed with limited ductility in the cold state. For deep draw and complex shapes, and for the avoidance of spring-back, an aluminium hot stamping process (

Hot Form Quench Hot Form Quench (HFQ®) - an aluminium hot forming lightweighting technology - is an industrial stamping process for the production of deep drawn, precise and complex geometry ultra-high strength aluminium sheet components. It is the aluminium ho ...

) can be used, which forms a blank at a elevated temperature (~ 550 C) in a cooled die, leaving a part in W-temper condition before artificial aging to the T6 full strength state.

Forgings

6061 is an alloy that is suitable for hot

forging Forging is a manufacturing process involving the shaping of metal using localized compression (physics), compressive forces. The blows are delivered with a hammer (often a power hammer) or a die (manufacturing), die. Forging is often classif ...

. The billet is heated through an

induction furnace An induction furnace is an electrical furnace in which the heat is applied by induction heating of metal. Induction furnace capacities range from less than one kilogram to one hundred tons, and are used to melt iron and steel, copper, aluminu ...

and forged using a closed die process. This particular alloy is suitable for open die forgings. Automotive parts, ATV parts, and industrial parts are just some of the uses as a forging. Aluminium 6061 can be forged into flat or round bars, rings, blocks, discs and blanks, hollows, and spindles. 6061 can be forged into special and custom shapes.

Castings

6061 is not an alloy that is traditionally cast due to its low silicon content affecting the fluidity in casting. It can be suitably cast using a specialized centrifugal casting method. Centrifugally cast 6061 is ideal for larger rings and sleeve applications that exceed the limitations of most wrought offerings.

Equivalent materials

6061 Aluminium Equivalent Table

Standards

Different forms and tempers of 6061 aluminium alloy are discussed in the following standards:6061 (3.3214, H20, A96061) Aluminum
Retrieved on 2014-11-14. * ASTM B209: Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate * ASTM B210: Standard Specification for Aluminum and Aluminum-Alloy Drawn Seamless Tubes * ASTM B211: Standard Specification for Aluminum and Aluminum-Alloy Bar, Rod, and Wire * ASTM B221: Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes * ASTM B308/308M: Standard Specification for Aluminum-Alloy 6061-T6 Standard Structural Profiles * ASTM B483: Standard Specification for Aluminum and Aluminum-Alloy Drawn Tube and Pipe for General Purpose Applications * ASTM B547: Standard Specification for Aluminum and Aluminum-Alloy Formed and Arc-Welded Round Tube * ISO 6361: Wrought Aluminium and Aluminium Alloy Sheets, Strips and Plates

References

External links

Aluminum 6061 Properties

Aluminium alloy table

{{aluminium alloys 6061 Aerospace materials Silicon alloys Aluminium–silicon alloys Aluminium–magnesium–silicon alloys