Influences of Environment in Heat Treatment and Pre-Aging at Room Temperature on Age-Hardening of Ti–Mo Alloys

Moritaka Hida, Eiichi Sukedai, Yoshito Takemoto

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The influences of environment in solute heat treatment and aging, and pre-aging at room temperature on the age-hardening behavior of Ti-14 and 20 mass% Mo alloys at 623 K were studied by Vickers hardness measurements. The solution heat treatments were performed in vacuums of 1.3 mPa and 8 Pa. The atmosphere, a pure argon current and a vacuum were used as the environments during aging. The periods of pre-aging were 1.6×105 s for the short pre-aging and 1.0×106–3.7×107 s for the long one. The specimens which were solution heat treated in each vacuum and pre-aged for 1.6×105 s showed a two-stage hardening. The first stage seemed to be due to a product formed by the reaction of quenched-in vacancies, interstitial atoms and metallic atoms, and the second stage was due to the formation of aged omega phase as reported previously. The age-hardening behavior of the specimen pre-aged for a short period was more active than that of the specimen pre-aged for a long period in spite of the solution heat treatments in either vacuum. The role of quenched-in vacancies in the age-hardening behavior was very important in Ti-20 mass% Mo alloys in connection with the pre-aging at room temperature. The higher the oxygen content in the environments during aging, the greater became the hardness values of the surface layer and the interior of Ti-14 mass% Mo alloys.

Original languageEnglish
Pages (from-to)102-106
Number of pages5
JournalMaterials Transactions, JIM
Volume30
Issue number2
DOIs
Publication statusPublished - Jan 1 1989
Externally publishedYes

Keywords

  • aged omega phase
  • aging at low temperature
  • environment effects
  • titanium-molybdenum alloy
  • two stage hardening

ASJC Scopus subject areas

  • Engineering(all)

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