In-plane hybrid design and mechanical properties of Ti-6Al-4 V TPMS structures

Triply Periodic Minimal Surface (TPMS) porous structures are widely utilized in aerospace, automotive, and medical applications due to their high specific strength, large surface area, and uniform stress distribution. However, current research typically focuses on linear hybridization under unidirectional loading to improve mechanical properties. This approach frequently overlooks performance uncertainties in other loading directions. To address these limitations, this paper introduces an in-plane hybrid design strategy. This strategy aims to enhance mechanical properties and energy absorption capacity under different loading directions. Two novel hybrid configurations combining Gyroid and IWP topologies were fabricated from Ti-6Al-4 V using Laser Powder Bed Fusion (PBF-LB/M), alongside their uniform counterparts. Corresponding finite element models were established for all uniform and hybrid structures to perform quasi-static compression simulations. The specimens were analyzed for manufacturing quality, pore formation, and crack evolution using scanning electron microscopy. Furthermore, quasi-static mechanical properties were evaluated under two distinct loading directions (I and II). The simulated stress-strain curves, deformation patterns, and failure modes were compared with the experimental results to validate the models and clarify the deformation mechanism. Results demonstrate that the in-plane hybrid structures exhibit plateau stresses ranging from 90.87 to 99.90 MPa and specific energy absorption (SEA) values between 44.43 and 58.78 J/g. Compared to the uniform structures, both hybrid designs achieved higher SEA when loaded in direction I, with improvements of 15% and 27%, respectively. Notably, the G-IWP-2-I configuration demonstrated the most superior overall mechanical performance. These findings are expected to advance the application of TPMS structures in lightweight design for the aerospace and automotive engineering fields.