Metal

Indentation hardness

Arc (geometry)

Sediment

Micro arc oxidation

Engineering

Magnesium alloy

Biology

Metallurgy

Materials science

Deposition (geology)

Ultimate tensile strength

Equiaxed crystals

Physical chemistry

Paleontology

Mechanical engineering

Alloy

Microstructure

Composite material

Dimple

Chemistry

Electrode

Aluminium

Additive manufacturing

The present study focuses on the fabrication of 2219 aluminum alloy components using double-electrode gas metal arc (DE-GMA) based additive manufacturing (AM) capable of reducing deposition heat input while maintaining high deposition rates, and how the microstructure and mechanical properties of as-built parts are affected by the bypass current ratio which is a key factor that determines the heat input to deposited layers in DE-GMA based AM. The bypass current ratios with 0%, 50 %, 70 %, and 90 % were employed to deposit thin-walled parts. As the bypass current ratio increases, the equiaxed dendrite size in the top region decreases, cellular grains in the strip area disappear gradually, and equiaxed grains in the inner-layer area are slowly transformed into columnar grains. The bypass current exhibits little effect on microhardness and a significant influence on tensile properties. By changing the bypass current ratio from 0% to 70 %, the ultimate tensile strengths and the elongations in the vertical as well as the horizontal directions increase by 9.71 Mpa, 18.89 Mpa, 4.17 %, and 5.74 %, respectively. No orientation dependence on the ultimate tensile strength can be observed. Extensive dimples at the fractures show typical ductile fracture characteristics.

Microstructure and mechanical properties of 2219 aluminum alloy fabricated by double-electrode gas metal arc additive manufacturing