Characterization of Ti-6Al-4V alloy foams synthesized by space holder technique

Bor, Sakir
Ti-6Al-4V foams, biomedical candidate materials, were synthesized by powder metallurgical space holder technique as a result of evaporation of magnesium to achieve desired porosity content. Final products contained porosities in the range similar to 43-64% with an average macropore size between 485 and 572 mu m and a lamellar type Widmanstatten microstructure composed of alpha-platelets and beta-laths. Unlike the case of bulk Ti-6Al-4V alloy tested under compression loading, compression stress-strain curves of manufactured Ti-6Al-4V foams were similar to those of elastic-plastic foams, which contain a linear elastic region; a plateau stage: and a densification stage. In the plateau region deformation bands perpendicular to the compression axis were developed and cell collapsing took place together with the buckling and fracture of some of the cell walls and edges in a ductile manner. Calculated elastic modulus and yield strength were in the range 1.42-14.7 GPa and 28.2-150 MPa, respectively, and the foam mechanical properties were found to be dependent on micro porous cell wall properties, which in turn depends on neck size between powder particles. Around 330 MPa yield strength value was calculated for porous cell walls by the use of Ti-6Al-4V alloy powder samples sintered in loose and compacted conditions, which were utilized to simulate the cell wall structure of foams. In addition, overall mechanical properties of foam s were investigated considering macro porosity fraction, p(macro), and the yield strength of foams exhibited a power law dependence, similar to commonly used minimum solid area models, in the form of A*(1 - p(marco))(n), where the proportionality constant "A" was found to be the yield strength of micro porous cell walls.


Production and characterization of porous titanium alloys
Esen, Ziya; Bor, Şakir; Department of Metallurgical and Materials Engineering (2007)
In the present study, production of titanium and Ti6Al4V alloy foams has been investigated using powder metallurgical “space holder technique” in which magnesium powder were utilized to generate porosities in the range 30 to 90 vol. %. Also, sintering of titanium and Ti-6Al-4V alloy powders in loose and compacted condition at various temperatures (850-1250oC) and compaction pressures (120-1125 MPa), respectively, were investigated to elucidate the structure and mechanical properties of the porous cell walls...
Characterization of magnetite thin films produced by sol-gel processing
Eken, Ali Erdem; Özenbaş, Ahmet Macit; Department of Metallurgical and Materials Engineering (2008)
Magnetite (Fe3O4) thin films were prepared by a sol-gel process in which, a solution of iron (III) nitrate dissolved in ethylene glycol was applied on glass substrates by spin coating. Xerogel films were obtained by drying the coated films at 110 °C. The films were sintered between 300 °C and 450 °C in order to observe the phases existing in the films at different temperatures. Coating solution showed Newtonian behaviour and viscosity was found as 0.0215 Pa.s. DTA analysis showed that, sintering temperature...
Characterization of maghemite thin films prepared by sol-gel processing
Karakuşçu, Aylin; Özenbaş, Ahmet Macit; Department of Metallurgical and Materials Engineering (2006)
In this study, maghemite (γ-Fe2O3) thin films were prepared by chemical solution deposition on glass and quartz substrates. The solution was prepared by using 0.3 M iron (III) nitrate [Fe(NO3)3 - 9H2O] as precursor and dissolved in a mixture of 2-methoxyethanol and acetylacetone in a molar ratio of 20:2, by stirring the solution at RT for 2 hours. Substrates were prepared by either piranha etching method or ultrasonic cleaning method. The solution was spin coated on glass and quartz substrates at 1400 and 4...
Characterization of Ti6Al7Nb alloy foams surface treated in aqueous NaOH and CaCl2 solutions
Butev, Ezgi; ESEN, ZİYA; Bor, Sakir (2016-07-01)
Ti6Al7Nb alloy foams having 53-73% porosity were manufactured via evaporation of magnesium space holders. A bioactive 1 mu m thick sodium hydrogel titanate layer, NaxH2-xTiyO2y+1., formed after 5 M NaOH treatment, was converted to crystalline sodium titanate, Na2TiyO2y+1, as a result of post-heat treatment. On the other hand, subsequent CaCl2 treatment of NaOH treated specimens induced calcium titanate formation. However, heat treatment of NaOH-CaCl2 treated specimens led to the loss of calcium and disappea...
Processing of titanium foams using magnesium spacer particles
Esen, Z.; Bor, S. (2007-03-01)
Production of titanium foams using magnesium powders as spacer particles has been investigated. Titanium foams having porosities in the range 45-70% with an average pore size of around 525 mu m have been manufactured. The resultant yield strength and elastic moduli values were observed to vary in the range 15-116 MPa and 0.42-8.8 GPa, respectively. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Citation Formats
Z. ESEN and S. Bor, “Characterization of Ti-6Al-4V alloy foams synthesized by space holder technique,” MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, pp. 3200–3209, 2011, Accessed: 00, 2020. [Online]. Available: