Mechanical and Fatigue Performance of Porous Tantalum Scaffolds with Composite Pore Structures Fabricated via Electron Beam Powder Bed Fusion

Porous tantalum scaffolds with composite pore structures, combining cubic and dodecahedron unit cells, are designed and fabricated using electron beam powder bed fusion. The static compressive and compressive fatigue properties of these composite scaffolds, featuring varying combination directions, are systematically investigated. Notably, under the equal strain condition, the elastic modulus and compressive yield strength of the composite scaffold are 0.95 GPa and 41.5 MPa, respectively, which are higher than scaffold under equal stress state. During fatigue tests, initial failure initiates within the weaker dodecahedron structure under the equal stress model. Following the complete failure of this structure, local tensile stress induces fracture in the struts of the cubic, resulting in a compressive fatigue strength lower than that of a uniform dodecahedral structure. Conversely, under the equal strain model, the composite scaffold demonstrates reduced cyclic ratcheting strain and a slower crack propagation rate during compressive fatigue, contributing to its compressive fatigue strength of 30.1 MPa at 2 × 10 6 cycles, which is much higher than the scaffold under equal stress condition. These findings demonstrate the effectiveness of strain‐matched composite pore design in improving the mechanical reliability of porous tantalum scaffolds, offering valuable insights for advanced implant development.