Titanium aluminide (TiAl) alloys are promising high-temperature structural materials in the aerospace field. Additive manufacturing is a desirable process for fabricating TiAl alloys. In the process of wire arc additive manufacturing of TiAl alloys, Al-based and Ti-based wires were used as the feedstocks. However, it is hard to ensure the two different wires melt synchronously under the heat of one single arc, so the desired microstructures with γ (TiAl) phase and α₂ (Ti₃Al) phase are hard to obtain. A two-wire TOP-TIG-based additive manufacturing process for TiAl alloys is proposed in this paper. The Ti6Al4V wire and pure Al wire are used as the feedstocks. The Al wire is fed in TOP-TIG mode behind the molten pool, while the Ti6Al4V wire is fed in conventional TIG mode in front of the molten pool. The two wires melt synchronously in a broad range of parameters. The compositions of the component can be controlled by adjusting the two-wire feeding speeds. The main microstructures of the as-fabricated component contain α₂/γ lamellae colonies, equiaxed γ grains, and α₂ grains. In the top and middle regions, when the Al content is 45 at.%, the structures are full α₂/γ lamellae; as the Al content increases to 50 at.%, some equiaxed γ grains distribute at the grain boundaries; the component with 55 at.% Al content exhibits the structures consists of equiaxed γ grains with snowflake-shaped α₂/γ lamellae colonies. In the bottom region, all components exhibit the coarse equiaxed α₂ grains with γ laths. As the Al content increases, the α₂ phase decreases, but the γ phase increases, and from the top region to the bottom region, the volume fraction of the α₂ increases by about 19.4 %. The hardness value of the top and bottom regions is higher, and the middle region exhibits the lowest hardness. As the Al content increases, the hardness decreases. The component with 50 at.% Al exhibits the highest compressive strength with 1762 MPa and the largest compressive ratio with 26.1%.

铝化钛（TiAl）合金在航空航天领域是很有前途的高温结构材料。增材制造是用于制造TiAl合金的理想工艺。在TiAl合金的电弧增材制造过程中，以Al基和Ti基丝为原料。然而，这是难以确保两个不同的导线同步熔体一个单一电弧的热量下，所以与γ（TiAl金属）相和α所需微结构₂（TI ₃Al）相很难获得。本文提出了一种基于两线TOP-TIG的TiAl合金增材制造工艺。使用Ti6Al4V焊丝和纯铝焊丝作为原料。Al丝以TOP-TIG模式送入熔池后，而Ti6Al4V丝以常规TIG模式送入熔池前。两条线在各种各样的参数中同步熔化。组分的组成可以通过调节两线进料速度来控制。所述的制成组件的主要微结构含有α ₂ /γ薄片菌落，等轴γ晶粒，和α _2个晶粒。在顶部和中部区域，当Al含量为45原子％，该结构是完全α ₂/γ薄片 当Al含量增加到50 at。％时，一些等轴γ晶粒分布在晶界处。原子％Al的含量表现出结构与55中的组分由等轴γ晶粒的雪花状的α ₂ /γ薄片菌落。在底部区域中，所有的部件表现出的等轴α粗_2个晶粒的γ板条。随着Al含量的增加，α ₂相减少，但γ相增加，并且从顶部区域到底部区域中，α的体积分数₂增加约19.4％。顶部和底部区域的硬度值较高，而中间区域的硬度最低。随着Al含量的增加，硬度降低。Al含量为50at。％的组分表现出最高的抗压强度，为1762 MPa，最大的压缩比为26.1％。