Recent research has focused on laser in-situ additive manufacturing of metal matrix composites with spatially controllable microstructures (phases). This study, inspired by the process of inserting mesh fibers into reinforced concrete, synthesizes TiN in situ using laser powder bed fusion and N₂ gas. The laser-melted track, embedded with TiN particles, formed a spatially heterostructured Ti composite (SHTC) with a three-dimensional, artificially controlled architecture in a pure Ti matrix. The influences of process parameters on the mechanical properties of the spatially heterostructured Ti composite and the microstructural evolution of TiN/Ti were investigated emphatically. The results showed that the growth direction of the microstructure was changed by laser powder bed fusion additive manufacturing with alternating N₂–Ar gas under suitable N₂ concentration and melting track spacing. Among all spatially heterostructured Ti composites, the TiN–Ti heterolayer net-like structure achieved a high ultimate tensile strength of ∼1.0 GPa and elongation of 27 %, demonstrating a superior strength-ductility combination than intrinsic pure Ti and uniform TiN composites, as well as traditional layered structure Ti-based composites. During the tensile test, the deformation behavior was monitored in situ using digital image correlation, and the fracture mechanism was investigated. Hetero-deformation induced strengthening and toughening potentially explains the mechanism behind the strength enhancement of spatially heterostructured Ti composites. Furthermore, this work may stimulate research and development in additive manufacturing of spatial heterostructures with configurable structures, targeting synergistic regulation of strength and ductility in the integration of structure-material-function.

最近的研究重点是具有空间可控微观结构（相）的金属基复合材料的激光原位增材制造。这项研究受到将网状纤维插入钢筋混凝土的过程的启发，利用激光粉末床熔融和 N₂气体原位合成 TiN。嵌入 TiN 颗粒的激光熔化轨道形成了空间异质结构钛复合材料 (SHTC)，该复合材料在纯钛基体中具有三维、人工控制的结构。重点研究了工艺参数对空间异质结构Ti复合材料力学性能的影响以及TiN/Ti微观结构演变。结果表明，₂浓度和熔道间距₂-Ar气体在所有空间异质结构钛复合材料中，TiN-Ti异质层网状结构实现了~1.0 GPa的高极限拉伸强度和27%的伸长率，表现出比本质纯Ti和均匀TiN复合材料更优异的强度-延展性组合。与传统的层状结构钛基复合材料一样。在拉伸试验过程中，利用数字图像相关技术现场监测变形行为，并研究断裂机制。异质变形诱导的强化和增韧可能解释了空间异质结构钛复合材料强度增强背后的机制。此外，这项工作可能会刺激具有可配置结构的空间异质结构增材制造的研究和开发，目标是在结构-材料-功能集成中对强度和延展性进行协同调节。