Study on the Selection and Fatigue Performance of Porous Bone Scaffolds Fabricated by Electron Beam Melting
Additive manufactured porous structure offers excellent mechanical biomimicry and osseointegration properties,supporting long-term stability of orthopedic implants in human body.This study employed triply periodic minimal surfaces(TPMS)method and Electron Beam Melting(EBM)technology to design and fabricate porous bone mimicking scaffolds.By investigating the pore characteristics,mechanical performance and fatigue life,a novel selection method suitable for bone implantable devices was proposed to meet the requirements of porosity connectivity,mechanical stability,and high-cycle fatigue life.Micro-CT and SEM characterization revealed the porous scaffolds with unit cell sizes≥1.5 mm had biomimetic pore sizes(748 µm)and good pore connectivity.The mechanical stability and reliability of TPMS-Gyroid scaffolds were superior to TPMS-Diamond.The established Gibson-Ashby equation in this work provided mechanical performance prediction for titanium alloy porous scaffolds.The fatigue life of the scaffolds exceeded 106 cycles at a stress level of 0.2,satisfying the long-term safety requirements for implant materials,with an elastic modulus similar to that of human cancellous bone(0.1～1.1 GPa).Furthermore,fatigue behavior studies also indicated that fatigue ratchet and fatigue damage were main causes of porous scaffold failure.In the design of metal porous scaffold's structure,the number of cracks could be reduced by increasing the size of the scaffold unit cell,which was helpful to improve the fatigue life of the scaffolds.
electron beam meltingtriply periodic minimal surfaceporous scaffoldmechanical propertyfatigue life
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