Cold metal transfer arc additive manufacturing technique was used to produce 5356 aluminum alloy by adding refining agents to solve the problems of coarse grains and poor performance. Metallic powders (Ti, TiH, and Ti+B₄C) were used to refine the grain size and promote the mechanical properties of the alloy. The effects of refining agents on the microstructure and mechanical properties of straight wall samples (SWSs) were studied. Samples with Ti+B₄C addition had a profound impact on morphology. However, the TiH added sample revealed uneven transition between sediment layers, unstable precipitation process, unstable wall height and wall width, poor morphology, and defects. All SWSs with powder addition revealed the formation of the Al₃Ti phase. Moreover, the columnar grains between the layers were transformed into equiaxed grains and finer grains at the center of the layers. There was a significant effect of TiH on the grain refinement. The samples with Ti demonstrated superior mechanical properties. The tensile strength and elongation of the SWSs increased by 28 MPa and 4.6% in the parallel additive direction and by 37 MPa and 8.9% in the vertical direction. The addition of Ti also contributed to the even distribution of the mechanical properties in both directions.

中文翻译：

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合金粉末对铝合金电弧增材制造显微组织和力学性能的影响

采用冷金属过渡弧增材制造技术生产5356铝合金，通过添加细化剂解决了晶粒粗大、性能差的问题。金属粉末（Ti、TiH 和 Ti+B ₄ C）用于细化晶粒尺寸并提高合金的机械性能。研究了精炼剂对直壁样品 (SWS) 的微观结构和力学性能的影响。添加Ti+B ₄ C 的样品对形态具有深远的影响。然而，添加TiH的样品显示沉积层之间过渡不均匀，沉淀过程不稳定，壁高和壁宽不稳定，形态差，存在缺陷。_{添加粉末的所有 SWS 均显示 Al 3}的形成钛相。此外，层间柱状晶在层中心转变为等轴晶和更细的晶粒。TiH 对晶粒细化有显着影响。含 Ti 的样品表现出优异的机械性能。SWSs 的拉伸强度和伸长率在平行添加方向增加了 28 MPa 和 4.6%，在垂直方向增加了 37 MPa 和 8.9%。添加 Ti 还有助于在两个方向上均匀分布机械性能。