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.

中文翻译：

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2219铝合金外填丝基GMA-AM工艺

摘要 焊丝加电弧增材制造 (WAAM) 追求高沉积速率，但代价是大热输入和对沉积层的严重热损伤。为了同时实现更高的沉积速率和更少的热损伤，本研究提出了一种基于外部填充焊丝的气体金属电弧增材制造 (EF-GMA-AM) 技术，其中将外部填充焊丝直接送入电弧以消耗电弧能量。通过对单层和多层 2219 铝合金进行导电，研究了外部填充焊丝进给速度 (EFWS) 对成形形貌、热损伤、显微组织和机械性能的影响。通过光学显微镜（OM）和扫描电子显微镜（SEM）观察微观结构。随着 EFWS 的增加，层高增加，重熔面积减少。将EFWS从0改为2.71 m/min，沉积速率提高可达80.3%，热损伤降低52.57%，中部细孔和粗柱状晶数量增加，硬度值降低从 87.45 到 80.20 HV，但拉伸性能几乎没有变化。拉伸断裂表现出典型的韧性断裂特征。