title: Relationship between unit cell type and porosity and the fatigue behavior of selective laser melted meta-biomaterials.
abstract: Meta-materials are structures when their small-scale properties are considered, but behave as materials when their homogenized macroscopic properties are studied. There is an intimate relationship between the design of the small-scale structure and the homogenized properties of such materials. In this article, we studied that relationship for meta-biomaterials that are aimed for biomedical applications, otherwise known as meta-biomaterials. Selective laser melted porous titanium (Ti6Al4V ELI) structures were manufactured based on three different types of repeating unit cells, namely cube, diamond, and truncated cuboctahedron, and with different porosities. The morphological features, static mechanical properties, and fatigue behavior of the porous biomaterials were studied with a focus on their fatigue behavior. It was observed that, in addition to static mechanical properties, the fatigue properties of the porous biomaterials are highly dependent on the type of unit cell as well as on porosity. None of the porous structures based on the cube unit cell failed after 10(6) loading cycles even when the applied stress reached 80% of their yield strengths. For both other unit cells, higher porosities resulted in shorter fatigue lives for the same level of applied stress. When normalized with respect to their yield stresses, the S-N data points of structures with different porosities very well (R(2)>0.8) conformed to one single power law specific to the type of the unit cell. For the same level of normalized applied stress, the truncated cuboctahedron unit cell resulted in a longer fatigue life as compared to the diamond unit cell. In a similar comparison, the fatigue lives of the porous structures based on both truncated cuboctahedron and diamond unit cells were longer than that of the porous structures based on the rhombic dodecahedron unit cell (determined in a previous study). The data presented in this study could serve as a basis for design of porous biomaterials as well as for corroboration of relevant analytical and computational models.
authors.affiliation: Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628 CD, The Netherlands. Electronic address: s.aminyavari@tudelft.nl.
authors.forename: S
authors.initials: S
authors.lastname: Amin Yavari
authors.affiliation: Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628 CD, The Netherlands.
authors.forename: S M
authors.initials: SM
authors.lastname: Ahmadi
authors.affiliation: KU Leuven, Department of Mechanical Engineering, Division of Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven, Belgium; LayerWise NV, Kapeldreef 60, 3001 Leuven, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Wauthle
authors.affiliation: Department of Orthopedics and Department of Rheumatology, University Medical Center Utrecht, Heidelberglaan100, 3584CX Utrecht, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Pouran
authors.affiliation: KU Leuven, Department of Metallurgy and Materials Engineering, Kasteelpark Arenberg 44, PB2450, 3001 Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Schrooten
authors.affiliation: Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628 CD, The Netherlands; Department of Orthopedics and Department of Rheumatology, University Medical Center Utrecht, Heidelberglaan100, 3584CX Utrecht, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Weinans
authors.affiliation: Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628 CD, The Netherlands.
authors.forename: A A
authors.initials: AA
authors.lastname: Zadpoor
mesh_terms: D000497:Alloys; D001672:Biocompatible Materials / Q000737:chemistry*; D007834:Lasers; D008422:Materials Testing; D008958:Models, Molecular; D008968:Molecular Conformation; D044367:Phase Transition; D016062:Porosity; D013314:Stress, Mechanical; D013329:Structure-Activity Relationship; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium
keywords: Additive manufacturing; Cellular solids; Failure; Geometry; Ti6Al4V ELI