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.