Development and characterizations of graded porous titanium scaffolds via selective laser melting for orthopedics applications
(1. National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing, Institute of Engineering Technology, University of Science and Technology Beijing, Beijing 100083, China;
2. Shunde Innovation School, University of Science and Technology Beijing, Foshan 528399, China;
3. Beijing Advanced Innovation Center for Materials Genome Engineering, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China;
4. Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore HA7 4LP, UK;
5. National Engineering Technology Research Center of Flat Rolling Equipment, Institute of Engineering Technology, University of Science and Technology Beijing, Beijing 100083, China;
6. Institute of Artificial Intelligence, University of Science and Technology Beijing, Beijing 100083, China)
2. Shunde Innovation School, University of Science and Technology Beijing, Foshan 528399, China;
3. Beijing Advanced Innovation Center for Materials Genome Engineering, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China;
4. Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore HA7 4LP, UK;
5. National Engineering Technology Research Center of Flat Rolling Equipment, Institute of Engineering Technology, University of Science and Technology Beijing, Beijing 100083, China;
6. Institute of Artificial Intelligence, University of Science and Technology Beijing, Beijing 100083, China)
Abstract: To improve the treatment effect of bone defect repair, titanium scaffolds having graded structures with porosities of 78.8%, 70.8%, 62.6%, and 54.4% (denoted as P1, P2, P3, and P4, respectively) were designed and fabricated by selective laser melting. The manufacturability, microstructure, mechanical properties, and permeability were investigated theoretically and experimentally. Simulation results showed that the maximum von Mises stress and permeability were in the range of 569.1-1469.0 MPa and (21.7-54.6)×10-9 m2 respectively. Thereinto, P3 and P4 exhibited lower maximum von Mises stress, meaning a higher strength. The microstructure of fabricated scaffolds with P3 and P4 consisted of martensitic α'''' phase. The yield strength and elastic modulus were 185.3-250.8 MPa and 6.1-9.7 GPa, respectively. Compared with the scaffold with P3, the scaffold with P4 exhibited higher yield strength and a more matched elastic modulus to cortical bone, and its permeability (18.6×10-9 m2) was within the range of permeability of human bone. Comprehensively, the scaffold with P4 is a promising candidate for bone defect reconstructions.
Key words: graded porous titanium; bone implants; selective laser melting; mechanical properties; permeability