In this work, TC4 titanium alloy CMT additive thin-walled components is selected as base metal to study the weld formation, microstructure evolution, and microhardness of TIG welded joint. The results showed that the thin-walled components could obtain a good formation after TIG welding. The weld seam was mainly consisted of equiaxed and columnar of β grain. The maximum texture intensity of β phase in the weld surface was only 10.746. Therefore, there was no obvious preferred growth direction in the weld seam. The heat affected bands (HAB) in the zone of weld seam was disappeared due to the base metal no undergone multiple heating cycles after melting. In the weld cross-section and weld surface, the average hardness of base metal is about 334.5 HV and 358.8 HV, respectively. The hardness of weld seam was greater than that of the base metal. The hardness of weld surface was greater than that of weld cross-section. The change of hardness of welded joint was mainly caused by β grain size and α phase.

中文翻译：

---

TC4 增材制造组件 TIG 焊接中焊接接头的焊缝外观、显微组织演变和显微硬度


本工作选择TC4钛合金CMT添加剂薄壁构件作为母材，研究TIG焊接接头的焊缝成型、显微组织演变和显微硬度。结果表明，薄壁构件TIG焊接后可获得良好的成形效果。焊缝主要由等轴晶和柱状β晶粒组成。焊缝表面β相织构强度最大仅为10.746。因此，焊缝中不存在明显的优选生长方向。由于母材熔化后未经过多次加热循环，焊缝区域的热影响带（HAB）消失。在焊缝截面和焊缝表面，母材平均硬度分别约为334.5 HV和358.8 HV。焊缝的硬度大于母材的硬度。焊缝表面硬度大于焊缝截面硬度。焊接接头硬度的变化主要是由β晶粒尺寸和α相引起的。