Impact of Layering Strategies on the Properties of In Situ Synthesized TiN/TC4 Laminated Materials via Laser-Directed Energy Deposition

Laser-directed energy deposition (LDED) additive manufacturing presents significant advantages for fabricating laminated materials with enhanced mechanical properties. This study investigates the in situ synthesis of TiN/TC4 laminated materials, developed using different layering strategies in the LDED process under alternating atmospheres of pure argon and nitrogen–argon gas mixtures. The effects of these layering strategies on the microstructure and mechanical properties of the synthesized materials are systematically analyzed. As the proportion of in situ synthesized layers increases, significant microstructural evolution is observed: the average grain size increases, the structure transitions from a Widmanstätten pattern to a basketweave structure, and the grain morphology shifts from columnar to equiaxed crystals. Correspondingly, the elongation at fracture decreases, while tensile strength initially increases and then declines. Notably, the 2-1 layering strategy achieves a peak tensile strength of 1135.0 ± 26.8 MPa, reflecting a 21.6% improvement compared to titanium alloy samples fabricated in a pure argon atmosphere. This study highlights the versatility of combining LDED with controlled deposition atmospheres to enable the tailored synthesis of laminated materials. The ability to manipulate microstructure and mechanical properties through specific layering strategies offers significant potential for advancing the development and application of high-performance laminated materials.