Influence of the structural orientation on the mechanical properties of selective laser melted Ti6Al4V open-porous scaffolds. (5th April 2016) - Weißmann, Volker
Abstract: In order to reduce the implant stiffness, open-porous designs in two geometrical dimensions were investigated (twisted design). Scaffolds were fabricated by an SLM process using Ti6Al4V and material properties were determined by conducting uniaxial compression testing. Furthermore, the unit cell was tested in different orientations to determine the mechanical properties. The elastic modulus of the scaffolds varied between 3.4 and 26.3 GPa and scaffolds porosity ranged from 54 to 60%. Linear relationship was found between compression strain, compressive strength and modulus of elasticity. Results show a clear influence of the unit cell orientation on elastic modulus, compressive strength and strain. Moreover, the specific yielding that characterizes the relationship between modulus of elasticity and porosity under consideration of the cell orientation could be described in functional terms. We successfully generated scaffolds with mechanical properties close to those of human cortical bone. The influence on the unit cell orientation demonstrated the necessity of considering the load direction in the evaluation of bone scaffolds. Graphical abstract: Highlights: The mechanical properties of Ti6AL4V porous structures (twisted design) are affected by geometric relations of the unit cell. They are also controlled by the orientation of struts to the applied force and the orientation of struts in building process. The specific yielding described the relationship between elastic modulus and porosity of porous structures by a power law.