We manufactured a Ti-based alloy via electron beam powder bed fusion (PBF-EB) and systematically investigated its microstructure and mechanical properties. We compared its properties with those of a conventionally forged alloy via electron backscattered diffraction, high-angle annular dark-field scanning transmission electron microscopy observations, and tensile tests. The formation mechanism, orientation relationship with the matrix, and crystal structures of the nanosized TiB particles were verified. The formation of nanosized TiB particles was mainly attributed to high cooling rates during PBF-EB manufacturing. In addition, the segregation of the solute Zr and Si atoms into the α-phase/TiB interface restricted TiB precipitate growth, which contributed to the formation of fine TiB particles in the alloy manufactured via PBF-EB. The orientation relationships between the TiB particles and α-phase in the PBF-EB-manufactured alloy are different from those in the hot-forged alloy. Moreover, for the first time, the simultaneous existence of the B27 and twinned B27 structures was verified in the nanosized TiB particles. Our study provides general guidelines for the manufacturing of materials strengthened by refined precipitates using PBF-EB or other additive manufacturing methods.

我们通过电子束粉末床熔化（PBF-EB）制造了钛基合金，并系统地研究了其微观结构和力学性能。通过电子反向散射衍射，高角度环形暗场扫描透射电子显微镜观察和拉伸试验，我们将其性能与常规锻造合金进行了比较。验证了纳米TiB颗粒的形成机理，与基体的取向关系以及晶体结构。纳米TiB颗粒的形成主要归因于PBF-EB制造过程中的高冷却速率。另外，溶质Zr和Si原子向α-相/ TiB界面的偏析限制了TiB沉淀物的生长，这有助于在通过PBF-EB制造的合金中形成TiB细颗粒。在PBF-EB制造的合金中，TiB颗粒与α相之间的取向关系不同于热锻合金中的取向关系。此外，首次在纳米TiB颗粒中验证了B27和孪生B27结构的同时存在。我们的研究为使用PBF-EB或其他增材制造方法通过精制沉淀物增强材料的制造提供了一般指导。