A comparative study on biodegradation and mechanical properties of pressureless infiltrated Ti/Ti6Al4V-Mg composites

2016-10-01
ESEN, ZİYA
Butev, Ezgi
Karakas, M. Serdar
The mechanical response and biodegradation behavior of pressureless Mg-infiltrated Ti-Mg and Ti6Al4V-Mg composites were investigated by compression and simulated body fluid immersion tests, respectively. Prior porous preforms were surrounded uniformly with magnesium as a result of infiltration and the resultant composites were free of secondary phases and intermetallics. Although the composites' compressive strengths were superior compared to bone, both displayed elastic moduli similar to that of cortical bone and had higher ductility with respect to their starting porous forms. However, Ti-Mg composites were unable to preserve their mechanical stabilities during in-vitro tests such that they fractured in multiple locations within 15 days of immersion. The pressure generated by H-2 due to rapid corrosion of magnesium caused failure of the Ti-Mg composites through sintering necks. On the other hand, the galvanic effect seen in Ti6Al4V-Mg was less severe compared to that of Ti-Mg. The degradation rate of magnesium in Ti6Al4V-Mg was slower, and the composites were observed to be mechanically stable and preserved their integrities over the entire 25-day immersion test. Both composites showed bioinert and biodegradable characteristics during immersion tests and magnesium preferentially corroded leaving porosity behind while Ti/Ti6Al4V remained as a permanent scaffold. The porosity created by degradation of magnesium was refilled by new globular agglomerates. Mg(OH)(2) and CaHPO4 phases were encountered during immersion tests while MgCl2 was detected during only the first 5 days. Both composites were classified as bioactive since the precipitation of CaHPO4 phase is known to be precursor of hydroxyapatite formation, an essential requirement for an artificial material to bond to living bone.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS

Suggestions

Analysis of the thermoviscoplastic behavior of [0/90] SCS-6/timetal®21S composites
Çöker, Demirkan; Nicholas, Theodore (1996-01-01)
Micromechanical modeling is used to determine the stresses and strains due to both mechanical and thermal loads in [0/90] titanium matrix composites (TMCs) subjected to cooldown from the processing temperature and subsequent thermomechanical fatigue (TMF) loading conditions. The [0/90] composite is treated as a material system composed of three constituents: fiber and matrix in the [0] ply, and a [90] ply. The [0/90]s layup is modeled by a uniaxial stress rule of mixtures model for the [0] ply and adding a ...
Three-dimensional modeling of intersonic shear-crack growth in asymmetrically loaded unidirectional composite plates
Yu, C.; Pandolfi, A.; Ortiz, M.; Çöker, Demirkan; Rosakis, A.J. (Elsevier BV, 2002-12)
An anisotropic cohesive model of fracture is applied to the numerical simulation of Coker and Rosakis experiments (2001). In these experiments, a unidirectional graphite-epoxy composites plate was impacted with a projectile, resulting in an intersonic shear-dominated crack growth. The simulations account for explicit crack nucleation-through a self-adaptive remeshing procedure-crack closure and frictional sliding. The parameters used in the cohesive model are obtained from quasi-static fracture experiments,...
A study on hydroxyl terminated polyether based composite propellants
Eşiyok, Hacı; Yılmazer, Ülkü; Department of Chemical Engineering (2016)
The present study was aimed at investigating the effects of isocyanate, chain extender and curing catalyst types on the mechanical, structural and thermal properties of Hydroxyl Terminated Polyether (HTPE) based gumstock samples and the effects of oxidizer, energetic plasticizer, and ballistic modifier types on the ballistic and thermal properties of propellant samples. HTPE based polyurethane networks were synthesized by hand mixing and applying vacuum for degassing of resulting mixtures. After curing, the...
A comparison of orthogonal cutting data from experiments with three different finite element models
Bil, H; Kilic, SE; Tekkaya, AE (Elsevier BV, 2004-07-01)
The aim of this study is to compare various simulation models of orthogonal cutting process with each other as well as with the results of various experiments. Commercial implicit finite element codes MSC.Marc, Deform2D and the explicit code Thirdwave AdvantEdge have been used. In simulations, a rigid tool is advanced incrementally into the deformable workpiece which is remeshed whenever needed. In simulations with MSC.Marc and Thirdwave AdvantEdge, there is no separation criterion defined since chip format...
A Computational analysis on rotor-propeller arm interaction in hovering flight
Yener, Serkan.; Perçin, Mustafa; Department of Aerospace Engineering (2019)
This study presents a computational analysis on the interaction between rotor and different rotor frame-arm geometries in hovering flight. The influence of the frame arm on the aerodynamic performance of the rotor is assessed by using commercially available computational fluid dynamics (CFD) solver software ANSYS Inc. Fluent 17. Numerical results are validated for hovering and forward vertical climb flight conditions with thrust and torque measurements conducted on a 16x4 carbon fiber propeller. The thrust ...
Citation Formats
Z. ESEN, E. Butev, and M. S. Karakas, “A comparative study on biodegradation and mechanical properties of pressureless infiltrated Ti/Ti6Al4V-Mg composites,” JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, pp. 273–286, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/66614.