Effect of microstructure on fracture characteristics of Ti-6Al-2Sn-2Mo-2Zr-2Cr-Si alloy

Mitsuo Niinomi, Kei ichi Fukunaga, Genzo Tono, Junichi Koike, Daniel Eylon, Shiro Fujishiro

Research output: Contribution to journalArticlepeer-review

Abstract

Ti-6Al-2Sn-4Zr-2Mo-0.1Si (Ti-62222S) is highly expected to be widely used for structural aircraft materials because Ti-62222S shows both characteristics of α type alloys with excellent high temperature strength and creep resistance, and α + β type alloys with high fracture toughness and high strength. The intermetallics, Ti3Al, and silicides, precipitated in Ti-62222S during aging treatments decrease the strength and fracture toughness. However, the effect of each intermetallics on fracture characteristics of Ti-62222S is not yet clearly understood. Therefore, the fracture characteristics of Ti-62222S with only Ti3Al or only silicides precipitated by aging treatment were investigated with relating the matrix microstructure. 0.2% proof stress, tensile strength and elongation of the as-received material are much better than those of the aged materials. 0.2% proof stress and tensile strength of the material with only Ti3Al precipitated by aging treatment are better than those of the material with only silicides precipitated by aging treatment, while elongation of the material with only silicides is better than that of the material with only Ti3Al. Static fracture toughness of the material with only silicides is better than that of the material with only Ti3Al. The intergranular fracture appears in the material with only Ti3Al. Coarsening of Widmanstaetten α structure and increasing ductility of β phase during aging is considered to be effective for increasing static fracture toughness.

Original languageEnglish
Pages (from-to)55-62
Number of pages8
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Volume87
Issue number1
DOIs
Publication statusPublished - 2001

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Metals and Alloys
  • Materials Chemistry

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