Effects of bio-functionalizing surface treatments on the mechanical behavior of open porous titanium biomaterials.
Bio-functionalizing surface treatments are often applied for improving the bioactivity of biomaterials that are based on otherwise bioinert titanium alloys. When applied on highly porous titanium alloy structures intended for orthopedic bone regeneration purposes, such surface treatments could significantly change the static and fatigue properties of these structures and, thus, affect the application of the biomaterial as bone substitute. Therefore, the interplay between biofunctionalizing surface treatments and mechanical behavior needs to be controlled. In this paper, we studied the effects of two bio-functionalizing surface treatments, namely alkali-acid heat treatment (AlAcH) and acid-alkali (AcAl), on the static and fatigue properties of three different highly porous titanium alloy implants manufactured using selective laser melting. It was found that AlAcH treatment results in minimal mass loss. The static and fatigue properties of AlAcH specimens were therefore not much different from as-manufactured (AsM) specimens. In contrast, AcAl resulted in substantial mass loss and also in significantly less static and fatigue properties particularly for porous structures with the highest porosity. The ratio of the static mechanical properties of AcAl specimens to that of AsM specimen was in the range of 1.5-6. The fatigue lives of AcAl specimens were much more severely affected by the applied surface treatments with fatigue lives up to 23 times smaller than that of AsM specimens particularly for the porous structures with the highest porosity. In conclusion, the fatigue properties of surface treated porous titanium are dependent not only on the type of applied surface treatment but also on the porosity of the biomaterial.
Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; FT Innovations BV, Braamsluiper 1, 5831 PW Boxmeer, The Netherlands. Electronic address: s.aminyavari@tudelft.nl.
S
S
Amin Yavari
Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
S M
SM
Ahmadi
Orthopaedic Research Laboratory, Department of Orthopedics, Erasmus University Rotterdam Medical Centre, Rotterdam, The Netherlands.
J
J
van der Stok
KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven, Belgium; LayerWise NV, Kapeldreef 60, Leuven, Belgiume.
R
R
Wauthle
Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
A C
AC
Riemslag
Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
M
M
Janssen
Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 - PB2450, B-3001 Heverlee, Belgium.
J
J
Schrooten
Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands; Department of Orthopedics & Department of Rheumatology, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
H
H
Weinans
Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, The Netherlands.
A A
AA
Zadpoor
D000497:Alloys; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D055119:Elastic Modulus; D006361:Heating; D006851:Hydrochloric Acid / Q000737:chemistry*; D008422:Materials Testing; D016062:Porosity; D012972:Sodium Hydroxide / Q000737:chemistry*; D013314:Stress, Mechanical; D013464:Sulfuric Acids / Q000737:chemistry*; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*
D000497:Alloys; D020099:Coated Materials, Biocompatible; D013464:Sulfuric Acids; C031462:titanium alloy (TiAl6V4); D012972:Sodium Hydroxide; D014025:Titanium; C033158:sulfuric acid; D006851:Hydrochloric Acid
Additive manufacturing; Chemical surface modifications; Fatigue; Mechanical testing; Open cellular materials; Titanium alloy