High-strength Ti-Mg interface with 3D interlocking structure via Ti mesh interlayer: fabrication, microstructure, and mechanical properties

Composite materials combining titanium (Ti) and magnesium (Mg) alloys promise synergistic benefits—lightweight, high strength, corrosion resistance , and biocompatibility, but their development is stymied by the inability of Ti and Mg to form a strong metallurgical bond. To address this issue, a two-step method is proposed: first diffusion-weld the Ti mesh to the TC4 substrate, then hot-press sinter AZ91 Mg alloy into the mesh pores to form a three-dimensional(3D) interlocking interface. The resulting 3D interlock mechanically locks the two phases, redirecting load away from the inherently weak Ti-Mg phase boundary into the stronger Ti mesh and Mg matrix. Finite-element analysis and microstructural characterization confirm this transition from a planar to a volumetric stress field. Under optimized conditions, the interface attains a tensile strength of 147.8 MPa (66.8 % of the Mg matrix) and a shear strength of 110.5 MPa (84.8 % of the Mg matrix), substantially outperforming conventional flat-interface joints. Beyond the Ti-Mg system, this design paradigm can be extended to bond dissimilar metals with weak metallurgical affinity—or even metal-nonmetal hybrids—provided the 3D-skeleton phase remains intact during densification, thereby offering a generalized solution for high-performance interfaces in multi-material assemblies.