5059 aluminium alloy is an aluminium–magnesium 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, 5059 can be readily welded and retain most of its mechanical strength.
5059 alloy was derived from closely related 5083 aluminium alloy by researchers at Corus Aluminium in 1999.
5059 has a density of 2660kg/m3, with a specific gravity of 2.66.
Melting point is 590°C.
The alloy composition of 5059 is:[1]
The mechanical properties of 5059 vary significantly with hardening and temperature.[1]
Unhardened 5059 has a yield strength of 23abbr=onNaNabbr=on and ultimate tensile strength of 48abbr=onNaNabbr=on from -28C100C. At cryogenic temperatures it is slightly stronger; above 100°C its strength is reduced.
Elongation, the strain before material failure, is 24% at room temperature.
yield strength of 269abbr=onNaNabbr=on, ultimate tensile strength of 365abbr=onNaNabbr=on.Produced by Aleris under the AluStar brand.[2]
yield strength of 269abbr=onNaNabbr=on, ultimate tensile strength of 359abbr=onNaNabbr=on.Produced by Aleris under the AluStar brand.
H321 strain hardened 5059, with properties measured at 20°C, has yield strength of 39abbr=onNaNabbr=on, ultimate tensile strength of 54abbr=onNaNabbr=on, and elongation of 10%.
5059 has been used as a hull material for small aluminium boats or larger yachts. Its high strength and good corrosion resistance make it an excellent match for yachting.[3]
5059 has been tested for use in vehicle armor.[4]
5059 has been used for cryogenic propellant tanks for experimental reusable rocket vehicles.[5] [6]
5059 is often assembled using arc welding, typically MIG (for marine use) 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. The relatively low decrease in ultimate strength is extremely good performance for an aluminium alloy.