Bionic mechanical design and SLM manufacture of porous Ti6Al4V scaffolds for load-bearing cancellous bone implants.

In order to repair the load-bearing cancellous bone defect of the human lower extremity, the development of a porous scaffold with high porosity, appropriate pore size, low elastic modulus and high fatigue strength has been faced with great challenges. In this study, the Ti6Al4V coaxial scaffolds with five types of beam angles and three types of pore sizes were designed using CAD and fabricated with the use of SLM. The porous characteristics and mechanical properties of scaffolds were investigated systematically. The results show that the porosity of the coaxial scaffolds is 63-69%, and the pore size is 480-700 μm. Meanwihle, the elastic modulus and compressive strength of the coaxial scaffolds were 1.08-1.85 GPa, 40-88 MPa, respectively. Moreover, the fatigue strength of the coaxial scaffolds with 500-40°, 600-40°, 700-40° were 1387, 1110 and 420 MPa, respectively. The pore size and porosity of the coaxial scaffolds in our study satisfied the size requirements for bone cells growth. Meanwhile, the low elastic modulus and high fatigue strength of the scaffolds also met the bio-mechanical bearing requirements of cancellous bone implants. Our study provided a reference for the design of biomimetic cancellous bone implants with good dynamic load-bearing mechanical properties.