Effect of Filler Metal Type on Microstructure and Mechanical Properties of Fabricated NiAl Bronze Alloy Using Wire Arc Additive Manufacturing System

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 alpha platelets and dense lamellar eutectoid alpha + kappa(III) structure with beta ' 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 alpha phases and lamellar eutectoid alpha + kappa(III) structure in between.