【摘要】 采用基于冷弧工艺的电弧增材制造技术（CA-WAAM）制备具有细小等轴晶粒的AZ91镁合金薄壁构件，研究了增材制造过程中的熔滴过渡行为以及增材件的显微组织和力学性能。结果表明，冷弧工艺减少了液桥断裂瞬间产生的飞溅，有效缩短了熔滴过渡周期。沉积试样的显微组织呈现出粗晶和细晶交替分布的层状特征。在逐层沉积过程中，β相优先沿晶界析出和生长，细小的η-Al₈Mn₅相分散在α-Mg基体中。增材件的力学性能表现出各向同性的特点，试样垂直方向的极限抗拉强度和伸长率分别为282.7MPa和14.2%；试样硬度分布相对均匀，平均硬度值为HV 69.6。更多还原

【Abstract】 Thin walls of an AZ91 magnesium alloy with fine equiaxed grains were fabricated via cold arc-based wire arc additive manufacturing（CA-WAAM）, and the droplet transfer behaviours, microstructures, and mechanical properties were investigated. The results showed that the cold arc process reduced splashing at the moment of liquid bridge breakage and effectively shortened the droplet transfer period. The microstructures of the deposited samples exhibited layered characteristics with alternating distributions of coarse and fine grains. During layer-by-layer deposition, the β-phase precipitated and grew preferentially along grain boundaries, while the fine η-Al₈Mn₅ phase was dispersed in the α-Mg matrix. The mechanical properties of the CA-WAAM deposited sample showed isotropic characteristics. The ultimate tensile strength and elongation in the building direction（BD） were 282.7 MPa and 14.2%, respectively. The microhardness values of the deposited parts were relatively uniform, with an average value of HV 69.6.更多还原