Design, Preparation, and Mechanical Property Investigation of Ti–Ta 3D‐Auxetic Structure by Laser Powder Bed Fusion

In recent years, Ti–Ta alloy has become a hot material in orthopedic implants. At the same time, the metal lattice structure with a negative Poisson's ratio has a great prospect in the application of implants due to its unique mechanical properties. Herein, an antichiral three‐dimensional polyhedron (A3P) lattice structure with negative Poisson's ratio is designed. This lattice structure is prepared by laser powder bed fusion (LPBF) technology using Ti–Ta alloy as the feedstock material. The surface morphology and relative density of the Ti–Ta samples built with different laser scanning speeds are compared for the optimization of the Ti–Ta's LPBF parameter. Then, the A3P structure of the Ti–Ta alloy is fabricated using the optimized LPBF parameters. The negative Poisson's ratio effect of the A3P structure is verified by finite element analysis (FEA) and compared with experimental results. The compression test results show that the yield strength and elastic modulus of the A3P structure are 9.2 MPa and 0.14 GPa, respectively, which is suitable for the orthopedics application. A3P structure has higher fracture energy compared with diamond structure, indicating it can absorb more energy in the fracture process. A3P shows a promising prospect in the application of orthopedics implantation.