Distinctive mechanical responses of strut-based and triply periodic minimal surface (TPMS) Ti-6Al-4V diamond lattice structures produced by electron beam melting

Lattice structures exhibit exceptional specific strength and energy absorption, making them ideal for aerospace and biomedical applications. While both strut-based (Strut-D) and TPMS-based (triply periodic minimal surface-D) diamond lattice structures show promising mechanical performance, the fundamental differences in their deformation mechanisms and mechanical behavior remain unclear. In this work, Ti-6Al-4V Strut-D and TPMS-D structures with 20% volume fraction were fabricated via electron beam melting (EB-PBF) and their compressive behavior and microstructure were systematically investigated. Compared to Strut-D, TPMS-D structures demonstrate superior mechanical properties: elastic modulus increased by 18.0% (1.51 GPa vs 1.28 GPa), compressive strength enhanced by 28.9% (58.4 MPa vs 45.3 MPa), and energy absorption at densification improved by 57.8% (16.1 MJ m −3 vs 10.2 MJ m −3 ). Finite element analysis revealed that the continuous curved surfaces of TPMS-D disperse stress more uniformly, avoiding stress concentration at nodes and enabling more material to bear load. In contrast, Strut-D exhibits localized stress at strut-node junctions, leading to premature failure. This study clarifies the topological influence on mechanical responses and provides insights for designing high-performance lattice structures. • Strut-based and TPMS-based Ti-6Al-4V diamond lattice structures were produced by EBM. • Both samples have highly similar microstructure mainly consisting of α-laths. • TPMS-based structure has higher strength and energy absorption than Strut-based one. • TPMS-based structure has a better stress transition, relieving stress concentration. • TPMS-based structure has a higher structural efficiency.