Deformation behavior and microstructure characterization of A357 aluminum alloy welding wires used for wire arc additive manufacturing

Microstructure and mechanical responses of A357 aluminum alloy welding wires after different degrees of strain were studied. It is found that the grains are elongated and refined along the drawing direction, accompanying with cell structures and sub-grains with strain increasing. Meanwhile, the main contributions to the fibrous texture are Cube, Goss and Copper, i.e., <001> and <111> textures. With the increase of drawing strain, the volume fraction of the Copper texture first increases and then decreases, while that of the Goss texture increases monotonously. The yield strength sharply increases at low drawing strain, after reaching the maximum value of 144.7 MPa at the strain of 0.32 and it decreases slightly due to dynamic recrystallization. Interestingly, the elongation of the cold-drawn wires decreases steadily from 24.4% to 2.3% throughout the entire drawing process. In addition to the grain boundary strengthening and dislocation strengthening, the yield strength of the cold-drawn A357 wires is also impacted by the <111> texture.