Evolution of antiphase domains and γ lamellae in Ti-39at% Al single crystals

Yuichiro Koizumi, Kazuki Iwamoto, Takayuki Tanaka, Yoritoshi Minamino, Nobuhiro Tsuji

Research output: Contribution to journalConference article

Abstract

We studied antiphase domain (APD) growth and lamellar structure formation during isothermal annealing of Ti-39at%Al single crystals at α2+γ7dual phase temperature after quenching from a single phase state, intending to obtain a APD/lamellae mixed microstructure. It was examined whether such a microstructure provides a hardness higher than that obtained only by refining lamellar structure. The effect of plastic deformation prior to the annealing was also examined expecting an acceleration of γ lamellae formation through a preferential nucleation of γ-plates at dislocations. The lower was the annealing temperature, the smaller both the APD size and the lamellar spacing at the moment of a homogeneous lamellar structure formation tended to be, although naturally both the APD growth and the γ lamellae formation were slower. However, the APD size in the homogeneous lamellar structure was no smaller than 400 nm. A structure with finer APDs and finer lamellar structure was obtained by deforming the crystal before annealing since the lamellar structure formation was accelerated and the time for APD growth before the lamellar structure formation was shortened. For instance, a structure with an average lamellar spacing of 88 nm and an average APD size of 214 nm was obtained by deforming the crystals to 10 % plastic strain and subsequently annealing at 1073 K for 1×104 s, while no γ plate was obtained only by such an annealing without deformation.

Original languageEnglish
Pages (from-to)377-382
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Volume980
Publication statusPublished - 2007 Jun 29
Event2006 MRS Fall Meeting - Boston, MA, United States
Duration: 2006 Nov 272006 Nov 29

ASJC Scopus subject areas

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

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    Koizumi, Y., Iwamoto, K., Tanaka, T., Minamino, Y., & Tsuji, N. (2007). Evolution of antiphase domains and γ lamellae in Ti-39at% Al single crystals. Materials Research Society Symposium Proceedings, 980, 377-382.