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The anisotropy of wire-arc additively deposited nickel-aluminum bronze alloy is studied by microstructure observation and room temperature mechanical property testing. The applied heat treatments have effectively modified the as-fabricated {0 1 1} <2 1 1>, {1 1 1} <1 1 0> texture into {1 1 1}. According to the microstructures, the single tempering has resulted in lowest anisotropy while heat treatment with prior homogenization and quenching process induces even intensified annealing textures. However, as shown by the tensile tests, the quenching process is necessary for favorable mechanical properties in the wire-arc additive manufacturing fabricated nickel-aluminum bronze component; therefore, a balance between homogenization annealing and κ-phase precipitation is indicated. Meanwhile, the function of κ-phase precipitates on grain rotation and growth during post-production heat treatment is explained in detail. [ABSTRACT FROM AUTHOR]

In narrow gap gas metal arc welding (GMAW), it is useful to understand the arc behaviors to ensure the weld quality. Arc behaviors are strongly affected by the shielding gas composition. In this study, a three-component shielding gas mixture was used in tandem narrow gap pulsed GMAW, and the effect of its composition on arc behaviors and weld formation were investigated. The shielding gas included argon, carbon dioxide, and helium. The arc behaviors and electrical characteristics were recorded by a high-speed camera and an electrical signal acquisition system. The results show that the arc behaviors in different shielding gas are different. The arc expands and the arc length decreases with the increase of CO content or helium content. The arc is the widest when the shielding gas is 80%Ar10%CO10%He. The weld shape was observed, and it was found that the weld width increases first and then decreases with increasing of the CO content. When the helium content is below 15%, the weld width increases as the helium content increases, but when the helium is 15%, the weld width drops due to the decrease of arc length. When the helium content is above 15%, the weld width continues to increase as the helium content increases. The largest weld width can be obtained in 80%Ar10%CO10%He. [ABSTRACT FROM AUTHOR]