Mechanical behaviour of an optimised novel Ti6Al4V lattice structure fabricated via LPBF: “An experimental and FEA investigation”

Abstract

Critical-sized bone defects lack the inherent capacity for self-repair and require engineered bone scaffold structures to provide mechanical stability while facilitating osteointegration. Conventional lattice architectures often fail to reconcile high strength with elevated porosity due to discontinuous geometries and stress concentrations at nodal junctions. The Hexanoid (HH) scaffold, inspired by curved surfaces and exhibiting three-dimensional periodicity, has demonstrated superior in-silico cell proliferation but remains mechanically suboptimal. This study introduces a titanium-based Modified Hexanoid (MH) scaffold, engineered to enhance structural performance while retaining porosity conductive to bone ingrowth. Scaffolds were fabricated using Ti6Al4V alloy via Laser Powder Bed Fusion (L-PBF) and mechanically benchmarked against HH, Cubic (CU) and Circular (CR) scaffold structures. Quasi-static compression testing reveals that the MH scaffold achieved an elastic modulus of ∼9 GPa, a yield strength of ∼104 MPa, and a compressive strength of ∼154 MPa, representing improvements of 24 %, 58 %, and 37 %, respectively, over the HH design. The MH design maintained a porosity of approximately 73 %, exceeding HH (∼61 %) and being comparable to CU (∼77 %) and CR (∼76 %). By combining porosity similar to that of trabecular bone with mechanical properties approaching those of cortical bone, the MH scaffold overcomes the strength-porosity trade-off, demonstrating strong potential for load-bearing orthopaedic implants.