5086 aluminum
Encyclopedia
5086 is an aluminium alloy
, primarily alloyed with magnesium
. It is not strengthened by heat treatment, instead becoming stronger due to strain hardening, or cold mechanical working of the material.
Since heat treatment doesn't strongly affect the strength, 5086 can be readily welded and retain most of its mechanical strength. The good results with welding and good corrosion properties in seawater make 5086 extremely popular for building boat and yacht hulls
.
Melting point is 1090 °F (587.8 °C).
; 117 MPa) and ultimate tensile strength
of 38 ksi (262 MPa) from -18 F. At cryogenic temperatures it is slightly stronger: at -320 °F, yield of 19 ksi (131 MPa) and ultimate tensile strength of 55 ksi (379 MPa); above 212 °F (100 °C) its strength is reduced.
Elongation, the strain
before material failure, ranges from 46% at -320 °F, 35% at -112 °F, 32% at -18 °F, 22% at 68 °F (20 °C), 30% at 75 °F (24 °C), 36% at 212 °F (100 °C), and increases above there.
s or larger yacht
s. Its high strength and good corrosion resistance make it an excellent match for yachting.
5086 has a tendency to undergo Stress corrosion cracking
and is not used much in aircraft construction as a result.
5086 has been used in vehicle armor, notably in the M113 Armored Personnel Carrier
and M2 Bradley
Infantry fighting vehicle.
, typically MIG
or TIG
welding. The newer technique of Friction stir welding
has also been successfully applied but is not in common use.
Arc welding reduces mechanical properties to no worse than –O hardening condition. For –H116 base material, measured at 68 °F (20 °C) ambient temperature, yield strength decreases from 30 ksi (207 MPa) to 17 ksi (117 MPa) and ultimate strength from 42 ksi (290 MPa) to 38 ksi (262 MPa). The relatively low decrease in ultimate strength (about 10%) is extremely good performance for an aluminium alloy.
Aluminium alloy
Aluminium alloys are alloys in which aluminium is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories...
, primarily alloyed with magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
. It is not strengthened by heat treatment, instead becoming stronger due to strain hardening, or cold mechanical working of the material.
Since heat treatment doesn't strongly affect the strength, 5086 can be readily welded and retain most of its mechanical strength. The good results with welding and good corrosion properties in seawater make 5086 extremely popular for building boat and yacht hulls
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
.
Basic properties
5086 has a density of 0.096 lb/cuin, with a specific gravity of 2.66.Melting point is 1090 °F (587.8 °C).
Chemical properties
The alloy composition of 5086 is:- ChromiumChromiumChromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
- 0.05%–0.25% by weight - CopperCopperCopper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
- 0.1% maximum - IronIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
- 0.5% maximum - MagnesiumMagnesiumMagnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
- 3.5%–4.5% - ManganeseManganeseManganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
- 0.2%–0.7% - SiliconSiliconSilicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
- 0.4% maximum - TitaniumTitaniumTitanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
- 0.15% maximum - ZincZincZinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
- 0.25% maximum - Others each 0.05% maximum
- Others total 0.15% maximum
- Remainder AluminiumAluminiumAluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
Mechanical properties
The mechanical properties of 5086 vary significantly with hardening and temperature.–O hardening
Unhardened 5086 has a yield strength of 17 ksi (17,000 psiPounds per square inch
The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units...
; 117 MPa) and ultimate tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
of 38 ksi (262 MPa) from -18 F. At cryogenic temperatures it is slightly stronger: at -320 °F, yield of 19 ksi (131 MPa) and ultimate tensile strength of 55 ksi (379 MPa); above 212 °F (100 °C) its strength is reduced.
Elongation, the strain
Strain (materials science)
In continuum mechanics, the infinitesimal strain theory, sometimes called small deformation theory, small displacement theory, or small displacement-gradient theory, deals with infinitesimal deformations of a continuum body...
before material failure, ranges from 46% at -320 °F, 35% at -112 °F, 32% at -18 °F, 22% at 68 °F (20 °C), 30% at 75 °F (24 °C), 36% at 212 °F (100 °C), and increases above there.
–H116 hardening
H116 strain hardened 5086, with properties measured at 68 °F (20 °C), has yield strength of 30 ksi (207 MPa), ultimate tensile strength of 42 ksi (290 MPa), and elongation of 12%.Uses
5086 is the preferred hull material for small aluminium boatBoat
A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...
s or larger yacht
Yacht
A yacht is a recreational boat or ship. The term originated from the Dutch Jacht meaning "hunt". It was originally defined as a light fast sailing vessel used by the Dutch navy to pursue pirates and other transgressors around and into the shallow waters of the Low Countries...
s. Its high strength and good corrosion resistance make it an excellent match for yachting.
5086 has a tendency to undergo Stress corrosion cracking
Stress corrosion cracking
Stress corrosion cracking is the unexpected sudden failure of normally ductile metals subjected to a tensile stress in a corrosive environment, especially at elevated temperature in the case of metals. SCC is highly chemically specific in that certain alloys are likely to undergo SCC only when...
and is not used much in aircraft construction as a result.
5086 has been used in vehicle armor, notably in the M113 Armored Personnel Carrier
M113 Armored Personnel Carrier
The M113 is a fully tracked armored personnel carrier that has formed the backbone of the United States Army's mechanized infantry units from the time of its first fielding in Vietnam in April 1962. The M113 was the most widely used armored vehicle of the U.S...
and M2 Bradley
M2 Bradley
The Bradley Fighting Vehicle is an American fighting vehicle platform manufactured by BAE Systems Land and Armaments, formerly United Defense.As with other infantry fighting vehicles, the Bradley is designed to transport infantry with armor protection while providing covering fire to suppress enemy...
Infantry fighting vehicle.
Welding
5086 is often assembled using arc weldingArc welding
Arc welding is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct or alternating current, and consumable or non-consumable electrodes...
, typically MIG
Gas metal arc welding
Gas metal arc welding , sometimes referred to by its subtypes metal inert gas welding or metal active gas welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun...
or TIG
Tig
Tig may refer to:*Tig Notaro, an American stand-up comic*Tig, another name for tag *Alex "Tig" Trager, a character in Sons of AnarchyTIG may refer to:*Tungsten inert gas welding, aka gas tungsten arc welding...
welding. The newer technique of Friction stir welding
Friction stir welding
Friction-stir welding is a solid-state joining process and is used for applications where the original metal characteristics must remain unchanged as far as possible...
has also been successfully applied but is not in common use.
Arc welding reduces mechanical properties to no worse than –O hardening condition. For –H116 base material, measured at 68 °F (20 °C) ambient temperature, yield strength decreases from 30 ksi (207 MPa) to 17 ksi (117 MPa) and ultimate strength from 42 ksi (290 MPa) to 38 ksi (262 MPa). The relatively low decrease in ultimate strength (about 10%) is extremely good performance for an aluminium alloy.