Phase transformation of α″ martensite structure by aging in Ti-8 mass%Mo alloy

Yoshikazu Mantani, Yoshito Takemoto, Moritaka Hida, Akira Sakakibara, Mamoru Tajima

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The orthorhombic α″ martensite was formed in Ti-8 mass%Mo alloy by quenching from 1223 K. The purpose of this study was to investigate phase transformation of the α″ martensite structure by isothermal aging. In differential scanning calorimetry curve of the quenched specimen, an exothermic peak that indicated decomposition from the α″ martensite to α and β phases was observed near 780 K, so that isothermal aging was performed at 723 K and 923 K for 9.0 ks. Optical microscopy, X-ray diffraction and transmission electron microscopy were performed to these specimens. Band-like products that were composed of the single variant of ω phase were observed in the quenched α″ martensite structure. On the other hand, (111)α″ twins were observed in the 723 K-aged α″ martensite structure. The quenched α″ martensite structure indicated low elastic incline and good ductility, whereas the 723 K-aged α″ martensite structure indicated high yield stress and brittleness. It was pointed out that the ω products were formed to relax the volume expansion from the β phase to the α″ martensite, and the (111)α″ twins were formed during the isothermal aging at 723 K with the extinction of the ω products.

Original languageEnglish
Pages (from-to)385-391
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume69
Issue number4
DOIs
Publication statusPublished - Apr 2005

Keywords

  • Differential scanning calorimetry
  • Omega phase
  • Orthorhombic martensite
  • Titanium-molybdenum alloy
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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