*2.1. Materials*

The material employed in the present study is a 6060-T66 aluminum alloy. It belongs to the wrought aluminum–magnesium–silicon alloys (6xxx series), and it has been additionally solution heat-treated and artificially aged (T66). This alloy is especially optimized for extrusion processes and develops good tensile strength. It has remarkable corrosion resistance and good weldability. It is commonly used in engineering applications (e.g., railway, automotive industry, building construction, etc.).

In order to carry out the experimental program, four 1.8 m long tubular beams were employed. Two of them had an outer diameter of 312 mm and 6 mm thickness, with the other two beams having an outer diameter of 260 mm and 5 mm thickness. Table 1 gathers the nominal chemical composition of this aluminum alloy [25].


**Table 1.** Chemical composition (nominal) of Al6060-T66 [25].
