External filler wire based GMA-AM process of 2219 aluminum alloy

ABSTRACT

Wire plus arc additive manufacturing (WAAM) pursues high deposition rates at the expense of large heat input and severe thermal damage to deposited layers. Aiming at simultaneous higher deposition rate and less thermal damage, this study proposes an external filler wire based gas metal arc additive manufacturing (EF-GMA-AM) technology in which an external filler wire is fed directly into the arc to consume the arc energy. The effect of the external filler wire feed speed (EFWS) on the forming morphology, thermal damage, and microstructure and mechanical properties was investigated by conducting single-layer and multi-layer 2219 aluminum alloy. The microstructure was observed by optical microscopy (OM) and scanning electron microscope (SEM). As the EFWS increases, the layer height increases and the remelted area decreases. By changing the EFWS from 0 to 2.71 m/min, the increased deposition rate can reach 80.3%, the thermal damage decreases by 52.57%, the numbers of the fine cellular and the coarse columnar grains increase in the middle region, the hardness values decrease from 87.45 to 80.20 HV, but the tensile properties present little variation. Tensile fractures exhibit typical ductile fracture characteristics.

KEYWORDS:

• Additive
• manufacturing
• WAAM
• GMA
• appearance
• damage
• microstructure
• microhardness
• tensile
• properties

Additional information

Funding

This work was funded by National Natural Science Foundation of China, no. 51975491 and no. 61573293, Sichuan Science and Technology Program, no. 2020YFG0197 and no. 2019YFG0354, and the Fundamental Research Funds for the Central Universities, no. 2682019CX12.