Mechanical behavior and microstructure of compressed Ti foams synthesized via freeze casting

Péter Jenei, Hyelim Choi, Adrián Tóth, Heeman Choe, J. Gubicza

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18 Citations (Scopus)

Abstract

Pure Ti and Ti–5%W foams were prepared via freeze casting. The porosity and grain size of both the materials were 32–33% and 15–17 µm, respectively. The mechanical behavior of the foams was investigated by uniaxial compression up to a plastic strain of ~0.26. The Young׳s moduli of both foams were ~23 GPa, which was in good agreement with the value expected from their porosity. The Young׳s moduli of the foams were similar to the elastic modulus of cortical bones, thereby eliminating the osteoporosis-causing stress-shielding effect. The addition of W increased the yield strength from ~196 MPa to ~235 MPa. The microstructure evolution in the grains during compression was studied using electron backscatter diffraction (EBSD) and X-ray line profile analysis (XLPA). After compression up to a plastic strain of ~0.26, the average dislocation densities increased to ~3.4×1014 m−2 and ~5.9×1014 m−2 in the Ti and Ti–W foams, respectively. The higher dislocation density in the Ti–W foam can be attributed to the pinning effect of the solute tungsten atoms on dislocations. The experimentally measured yield strength was in good agreement with the strength calculated from the dislocation density and porosity. This study demonstrated that the addition of W to Ti foam is beneficial for biomedical applications, because the compressive yield strength increased while its Young׳s modulus remained similar to that of cortical bones.

Original languageEnglish
Pages (from-to)407-416
Number of pages10
JournalJournal of the Mechanical Behavior of Biomedical Materials
Volume63
DOIs
Publication statusPublished - Oct 1 2016

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Keywords

  • Dislocations
  • Freeze-casting
  • Plastic deformation
  • Ti-foam
  • Yield strength
  • Young׳s modulus

ASJC Scopus subject areas

  • Biomaterials
  • Biomedical Engineering
  • Mechanics of Materials

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