5059 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, 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.