Mechanical behaviors of tantalum scaffolds with node optimization fabricated by laser powder bed fusion

Tantalum scaffolds fabricated by laser powder bed fusion are promising load-bearing orthopedic implant materials because of their superior corrosion resistance and biocompatibility. Nevertheless, the stress concentration harms the mechanical performance and service life of the biomaterials. To alleviate this deficiency, dodecahedron porous tantalum scaffolds with various optimized radii were designed and fabricated. The influence of node optimization on the compressive mechanical property of porous tantalum scaffolds was investigated by compression testing, scanning electron microscopy (SEM), and finite element analysis (FEA). The as-built tantalum scaffolds were tightly connected and arranged neatly without apparently macroscopic defects. Due to the introduction of node optimization, the scaffolds with optimized radius at the node demonstrated enhanced mechanical properties and compressive capacity. The compressive yield strength and elastic modulus increased from 6.23 ± 0.83 MPa to 12.94 ± 0.94 MPa and from 0.25 ± 0.05 GPa to 0.39 ± 0.07 GPa, respectively, as the optimum radius grew from 0 to 200 μm. It was shown that the scaffolds displayed a progressive layer-by-layer collapse behavior combined with buckling and bending deformation. The results of the FEA were consistent with the compression tests and showed that adding an appropriate node optimization would relieve the stress concentration and increase the load-bearing capacity of porous tantalum scaffolds. •LPBF-fabricated dodecahedron lattice tantalum scaffolds with optimized radius showed better mechanical properties.•The as-build scaffolds exhibited a progressive layer-by-layer collapse behavior combined buckling and bending deformation.•With node optimiztion, the stress transferred to the interior of struts and a uniform stress distribution was realized.