The titanium powder embedded with 2.5 vol% TiB was in-situ fabricated by gas atomization and applied for direct laser deposited (DLD) titanium matrix composites. Consistent with the network distributed boron-rich zone in composite powder, a three-dimensional (3D) in-situ ultrafine network structure, consisting of nano-TiB whiskers (TiBw), was characterized throughout the as-fabricated composite (DLDed TiB–Ti). Both the dendritic and equiaxed network, attributed to the boron-induced constitutional supercooling and subsequent nucleation and growth of primary β-Ti, existed in the composite. The addition of boron (B) had a positive effect on the equiaxial transition and grain refinement of both primary β-Ti grains and α grains. Tensile tests showed an enhancement of strength compared with conventionally fabricated homogeneous TiB–Ti composites and selective laser melted CP-Ti. Analyzing the strength mechanism of the DLDed TiB–Ti, apart from the fine-grain strengthening and load-bearing effect of TiBw, the TiB network was found to have an additional contribution to the improvement of strength. Fracture morphology and in situ tensile observation showed the role of network structure in plastic deformation limitation, crack deflection and blunting, which was mainly attributed to the ultrafine cell size and revealed the significance of network structure.

通过气体雾化原位制备嵌入了2.5％（体积）TiB的钛粉，并将其用于直接激光沉积（DLD）钛基复合材料。与复合粉末中网络分布的富硼区一致，整个合成复合材料（DLDed TiB–Ti）均具有由纳米TiB晶须（TiBw）组成的三维（3D）原位超细网络结构。 ）。由于硼诱导的组织过冷以及随后的初级β-Ti形核和生长，导致了树枝状和等轴网络的存在。硼（B）的添加对一次β-Ti晶粒和α晶粒的等轴转变和晶粒细化具有积极作用。拉伸试验表明，与传统制造的均质TiB-Ti复合材料和选择性激光熔融CP-Ti相比，强度有所提高。分析DLDd TiB-Ti的强度机理，除了细晶粒的增强和TiBw的承重效果外，还发现TiB网络对强度的提高有其他贡献。断裂形态和原位拉伸观察表明网络结构在塑性变形限制，裂纹变形和钝化中的作用，这主要归因于超细孔尺寸，并揭示了网络结构的重要性。发现TiB网络对提高强度有额外的贡献。断裂形态和原位拉伸观察表明网络结构在塑性变形限制，裂纹变形和钝化中的作用，这主要归因于超细孔尺寸，并揭示了网络结构的重要性。发现TiB网络对提高强度有额外的贡献。断裂形态和原位拉伸观察表明网络结构在塑性变形限制，裂纹变形和钝化中的作用，这主要归因于超细孔尺寸，并揭示了网络结构的重要性。