Macrostructural and mechanical evaluation of butt‐welded AW‐6082 aluminium alloy connections

The welding of aluminium alloys significantly alters their mechanical behaviour, which directly affects the behaviour of structural aluminium connections and joints. This study focuses on butt‐welded connections made of EN AW‐6082‐T651 alloy, produced using pulsed MIG welding with both direct current (DC) and alternating current (AC), with emphasis on macrostructural and mechanical evaluation. Three plate thicknesses (6, 8 and 10 mm) were investigated to capture the influence of thickness on welding response. Macro examinations of weld cross‐sections were performed to assess weld quality and geometry. Hardness measurements revealed the lowest values in the weld metal, while the base material exhibited notable structural changes but less pronounced softening in heat‐affected zone (HAZ). In addition to metallurgical assessment, tensile tests were also conducted on welded and non‐welded coupons. The results showed a reduction in 0.2 proof and ultimate tensile strengths, with values above those prescribed in Eurocode 9, as well as reduced ductility in welded coupons compared to the base material. The presented results were used to evaluate the provisions codified in Eurocode 9 concerning the extent of the HAZ and the reduction of mechanical properties within this zone. The results obtained thus provide a valuable contribution to the refinement of design rules and the development of reliability models for welded aluminium structures in general.