To expand the application of wire-arc additive manufacturing (WAAM) in aluminum alloy forming components, it is vitally important to reduce the porosity, refine microstructure, and thereby improve the mechanical properties of the components. In this study, the interlayer friction stir processing (FSP) technique was employed to assist the WAAM of 4043 Al–Si alloy, and the related effects on the microstructure evolutions and mechanical properties of the fabricated builds were systematacially investigated. As compared to the conventional WAAM processing of Al–Si alloy, it was found that the introduction of interlayer FSP can effectively eliminate the pores, and both the α-Al dendrites and Si-rich eutectic network were severely broken up, leading to a remarkable enhancement in ductility and fatigue performance. The average yield strength (YS) and ultimate tensile strength (UTS) of the Al-based components produced by the combination of WAAM and interlayer FSP methods were 88 and 148 MPa, respectively. Meanwhile, the elongation (EL) of 37.5% and 28.8% can be achieved in the horizontal and vertical directions, respectively. Such anisotropy of EL was attributed to the inhomogeneous microstructure in the stir zone (SZ). Notably, the stress concentration can be effectively reduced by the elimination of porosity and Si-rich eutectic network fragmentation by the interlayer FSP, and thus the fatigue behavior was improved with the fatigue strength and elongation increased by ∼28% and ∼108.7%, respectively. It is anticipated that this study will provide a powerful strategy and theoretical guidance for the WAAM fabrication of Al-based alloy components with high ductility and fatigue performance.

为了扩大电弧增材制造（WAAM）在铝合金成型部件中的应用，降低孔隙率，细化微观结构，从而提高部件的机械性能至关重要。本研究采用层间搅拌摩擦加工 (FSP) 技术辅助 4043 Al-Si 合金的 WAAM，并系统地研究了其对所制造结构的微观结构演变和力学性能的相关影响。与传统的 WAAM 处理 Al-Si 合金相比，发现层间 FSP 的引入可以有效消除气孔，α-Al 枝晶和富硅共晶网络均被严重破坏，导致显着的提高延展性和疲劳性能。WAAM 和层间 FSP 方法相结合生产的铝基部件的平均屈服强度 (YS) 和极限抗拉强度 (UTS) 分别为 88 和 148 MPa。同时，水平和垂直方向的伸长率（EL）分别为37.5%和28.8%。EL 的这种各向异性归因于搅拌区 (SZ) 中的不均匀微观结构。值得注意的是，通过层间FSP消除孔隙和富Si共晶网络破碎可以有效降低应力集中，从而改善疲劳行为，疲劳强度和延伸率分别提高~28%和~108.7%。 .