Mechanical behavior of a titanium alloy scaffold mimicking trabecular structure

Area of Science:

• Biomaterials Engineering
• Orthopedic Implants
• Additive Manufacturing

Background:

• Additively manufactured porous metallic structures are gaining traction for bone implant applications.
• The mechanical behavior of 3D printed titanium alloy trabecular structures is crucial for artificial prosthesis efficacy but lacks in-depth study.
• Understanding the relationship between design, manufacture, structure, and mechanical function is vital.

Purpose of the Study:

• To systematically investigate the structural design, fabrication, and mechanical behavior of 3D printed titanium alloy scaffolds that mimic trabecular bone.
• To analyze the impact of microarchitecture modifications on the mechanical properties of these scaffolds.
• To evaluate the potential of these scaffolds in reducing stress shielding in bone implants.

Main Methods:

• Designed unit cells to mimic trabecular bone structure using titanium alloy.
• Fabricated scaffolds with varying pore sizes and porosities via Electron Beam Melting (EBM).
• Characterized structural differences, mechanical properties, collapse behavior, and failure mechanisms under quasi-static loading.

Main Results:

• Actual porosities were lower than designed; higher porosity correlated with lower stiffness and load capacity.
• Fracture interfaces aligned at 45° to the compressive axis, consistent with Tresca yield criterion.
• Scaffolds showed anisotropic behavior, with elastic modulus reduced by 93-96% and strength by 91-96% compared to dense titanium alloy, achieving values close to natural bone (0.39-0.618 GPa).

Conclusions:

• Systematic study of structural design, fabrication, and mechanical behavior of 3D printed titanium alloy trabecular bone mimics completed.
• Findings provide a foundation for developing prostheses with optimized structures and functions.
• The developed scaffolds show promise for reducing stress shielding in bone replacement applications.