Study and Characterization of EN AW 6181/6082-T6 and EN AC 42100-T6 Aluminum AlloyWelding of Structural Applications: Metal Inert Gas (MIG), Cold Metal Transfer (CMT), and Fiber Laser-MIG Hybrid Comparison

The present research investigates the eects of dierent welding techniques, namely
traditional metal inert gas (MIG), cold metal transfer (CMT), and fiber laser-MIG hybrid, on the
microstructural and mechanical properties of joints between extruded EN AW 6181/6082-T6 and cast
EN AC 42100-T6 aluminum alloys. These types of weld are very interesting for junctions of Al-alloys
parts in the transportation field to promote the lightweight of a large scale chassis. The weld joints
were characterized through various metallurgical methods including optical microscopy and hardness
measurements to assess their microstructure and to individuate the nature of the intermetallics,
their morphology, and distribution. The results allowed for the evaluation of the discrepancies
between the welding technologies (MIG, CMT, fiber laser) on dierent aluminum alloys that represent
an exhaustive range of possible joints of a frame. For this reason, both simple bar samples and
real junctions of a prototype frame of a sports car were studied and, compared where possible.
The study demonstrated the higher quality of innovative CMT and fiber laser-MIG hybrid welding
than traditional MIG and the comparison between casting and extrusion techniques provide some
inputs for future developments in the automotive field.