Effect of heterogeneous precipitation caused by segregation of substitutional and interstitial elements on mechanical properties of a β-type Ti alloy

Kengo Narita, Mitsuo Niinomi, Masaaki Nakai, Yalatu Su

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

This study investigates the effect of heterogeneous precipitation induced by the segregation of substitutional and interstitial elements in Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) on its mechanical properties. For this, samples both with and without segregation of substitutional elements were prepared, with only the latter being subjected to long-term homogenization. It was found that micro-scale segregation of substitutional elements such as Nb, Ta, and Zr does not significantly affect mechanical properties such as fatigue strength, not even if heterogeneous precipitation occurs as a result of this segregation. On the other hand, segregation of interstitial elements was achieved by controlling the aging time. The segregation of interstitial elements creates precipitate-free zones (PFZs), grain boundary (GB) plates, and Widmanstätten α phases with migrating O atoms that all significantly affect the mechanical properties. Specifically, the PFZs have the potential to improve fatigue life, while the Widmanstätten α phase increases the tensile strength and reduces the fatigue ratio, the GB-plates reduce elongation, These results indicate that the formation of a Widmanstätten α phase by the migration of interstitial elements has a varying influence on the tensile and fatigue properties.

Original languageEnglish
Pages (from-to)109-118
Number of pages10
JournalMaterials Science and Engineering A
Volume643
DOIs
Publication statusPublished - 2015 Sep 3

Keywords

  • Beta-type Ti alloy
  • Elemental segregation
  • Fatigue strength
  • Heterogeneous structure
  • Metallic biomaterial

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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