Production and characterization of porous titanium alloys

Download

index.pdf

Date

2007

Author

Esen, Ziya

Metadata

Show full item record

Item Usage Stats

120
views

39
downloads

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 present due to partial sintering of powders in the specimens prepared by space holder technique. In addition, microstructure and mechanical response of the porous alloys were compared with the furnace cooled bulk samples of Ti-6Al-4V-ELI alloy subsequent to betatizing. It has been observed that the magnesium also acts as a deoxidizer during foaming experiments, and its content and removal temperature is critical in determining the sample collapse. Stress-strain curves of the foams exhibited a linear elastic region; a long plateau stage; and a densification stage. Whereas, curves of loose powder sintered samples were similar to that of bulk alloy. Shearing failure in foam samples occurred as series of deformation bands formed in the direction normal to the applied load and cell collapsing occured in discrete bands. Average neck size of samples sintered in loose or compacted condition were found to be different even when they had the same porosity, and the strength was observed to change linearly with the square of neck size ratio. The relation between mechanical properties of the foam and its relative density, which is calculated considering the micro porous cell wall, was observed to obey power law. The proportionality constant and the exponent reflect the structure and properties of cell walls and edges and macro pore character.

Subject Keywords

Powder metallurgy, Metallurgy

URI

http://etd.lib.metu.edu.tr/upload/3/12608964/index.pdf
https://hdl.handle.net/11511/17171

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Production and characterization of high performance al – fe – v – si alloys for elevated temperature applications Sayılgan, Seda; Kalkanlı, Ali; Department of Metallurgical and Materials Engineering (2009) In the present study, the powder metallurgy was evaluated as a technique to produce high performance Al – 8Fe – 1.7V – 7.9Si (wt%) alloys for elevated temperature applications and the role of powder particle size range and extrusion ratio in the microstructural and mechanical properties of the extruded alloys was investigated. For this purpose, an air atomization method was employed to produce powders of the high temperature alloy and after that the produced powders were sieved and cold compacted. The compa...
Investigation of the effect of orientation and heat treatment on the stress corrosion cracking susceptibility of 7050 aluminium alloy Çevik, Gül; Doruk, Mustafa; Department of Metallurgical and Materials Engineering (2004) In the present work, the effect of variation in specimen orientation and heat treatment on the Stress Corrosion Cracking (SCC) susceptibility of 7050 aluminum alloy was investigated in 3,5% NaCl solution and under freely corroding conditions. For this purpose, Constant Extension Rate Tests (CERT) was performed on precracked Compact Tension (CT) specimens and the Direct Current Potential Drop technique was applied to measure the crack lengths. In addition to crack length versus time curves, the relationship ...
Characterization of Ti-6Al-4V alloy foams synthesized by space holder technique ESEN, ZİYA; Bor, Sakir (2011-03-25) 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...
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...

Citation Formats

Z. Esen, “Production and characterization of porous titanium alloys,” Ph.D. - Doctoral Program, Middle East Technical University, 2007.