Oxygen distribution in titanium single crystal fabricated by optical floating-zone method under extremely low oxygen partial pressure

Koji Hagihara, Takahiro Tachibana, Keita Sasaki, Yoshiyuki Yoshida, Naoki Shirakawa, Tohru Nagasawa, Takayuki Narushima, Takayoshi Nakano

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

This study examines the properties of a titanium single crystal fabricated by the floating-zone-melting process in Ar gas flow atmosphere where the partial pressure of oxygen was maintained extremely low at Po2 = ∼10-23 atm by the newly developed oxygen pump system. The distribution of solute oxygen atoms in the obtained single crystal exhibited a peculiar gradient. In the early stage of the titanium single crystal growth, the oxygen content in the single crystal (approximately 1600 ppm) was higher than that in the mother ingot (980 ppm). However, as the crystal growth progressed, the oxygen content gradually decreases and then reduced to 660 ppm in the final stage of crystal growth. Such a gradient of oxygen composition was not detected in titanium single crystals fabricated under conventional, commercial Ar gas flow atmosphere. Owing to the unique gradient of oxygen content formed under extremely low oxygen partial pressure, the Vickers hardness of the single crystal decreased gradually along the crystal growth direction.

Original languageEnglish
Pages (from-to)2709-2715
Number of pages7
JournalMaterials Transactions
Volume50
Issue number12
DOIs
Publication statusPublished - 2009 Dec

Keywords

  • Composition gradient
  • Crystal growth
  • Extremely low oxygen partial pressure
  • Floating-zone method
  • Oxygen concentration
  • Single crystal
  • Titanium
  • Vickers hardness

ASJC Scopus subject areas

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

Fingerprint

Dive into the research topics of 'Oxygen distribution in titanium single crystal fabricated by optical floating-zone method under extremely low oxygen partial pressure'. Together they form a unique fingerprint.

Cite this