On the mechanical integrity of AA6082 3D structures deposited by hybrid metal extrusion & bonding additive manufacturing

Hybrid Metal Extrusion and Bonding Additive Manufacturing (HYB-AM) is a new solid-state process for the production of 3D metal structures. In HYB-AM, the wire feedstock is continuously processed through an extruder and deposited in a stringer-by-stringer manner to form layers and eventually a near net-shape component. In this work, the layer bonding of AA6082 samples produced by this process has been investigated by means of tensile testing, hardness measurements and microscope analyses. Furthermore, a novel method for the fabrication of miniature tensile specimens for assessing the bond strength across the layers is presented and applied. The test results reveal that the ultimate tensile strength is approaching that of the substrate material of the same alloy, yet with a somewhat lower elongation prior to fracture. Microscope analyses show that the bonded interfaces are fully dense; however, the fracture surfaces reveal regions of kissing-bonds and lack of bonding. Still, these preliminary investigations indicate that the HYB-AM process, upon further optimization, has the potential of processing high quality aluminum alloy components.