Abstract: Triply surface period Minimal surface (TPMS) lattice structures have a wide range of lightweight design prospects due to their lightweight, high strength and energy absorption properties, but are difficult to manufacture by traditional methods. Using Ti-6Al-4V powder as material, two lattice samples with different porosity of Gyroid and Primitive and solid tensile samples were prepared by selective laser melting (SLM) technique, and the mechanical properties and microstructure were analyzed. The results show that the mechanical properties of TPMS tend to decrease with the increase of porosity, and the plasticity of Primitive structure is better than that of Gyroid structure, but the overall strength is lower than that of Gyroid structure. The compressive yield strength and tensile strength of TPMS lattice structure reach 498MPa and 373MPa, and the mechanical properties of TPMS lattice structure are better than those based on bar diameter class (BCC, FCC), and the elongation of lattice structure is 2.8%~14% higher than that of solid sample. The fracture mode of the two lattice structures is a mixture of toughness and brittleness, and there are porosity and unfused powder on the surface of the lattice structures, which does not affect the failure mechanism. The tensile strength and elongation of the solid tensile sample prepared under the same process parameters reach 1050MPa and 17.5%, which is superior to the mechanical properties of traditional cast Ti-6Al-4V alloy.

Key words: Ti-6Al-4V, Selective laser melting (SLM), Three-period minimal surface (TPMS), Mechanical properties, Failure mechanism