^* CMT-ADV: CMT-Advanced, CMT-PADV: CMT-Pulse Advanced

It is expected that the application of aluminum alloy, a lightweight material, will continue to increase in connection with strengthening international environmental regulations and improving fuel efficiency for reducing vehicle emissions. Accordingly, aluminum alloys are widely applied to the automobile industry, and various welding methods are used for aluminum alloys. In this paper, the laser-arc hybrid welding method that combines laser and arc welding is explained. Although laser-arc hybrid welding has better weldability than a single heat source of laser or arc, the degradation of mechanical properties due to defects occurring during hybrid welding has emerged as a problem. This paper discussed the quality of aluminum alloy welds through optimization of various process parameters of hybrid welding.

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κ_III structure with β′ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κ_III structure in between.