Deformation of diffusion-bonded bi-PST and directionally solidified crystals of TiAl

Book · Wed Dec 31 04:00:00 EST 1997

OSTI ID:571703

Kishida, K; Johnson, D R; Masuda, Y; Inui, H; Yamaguchi, M ^[1]; Shimada, Y ^[2]

---

1. Kyoto Univ., Sakyo (Japan). Dept. of Materials Science and Engineering
2. Mitsubishi Electric Corp., Itami, Hyogo (Japan)

With a data base now available on the microstructural characteristics and the deformation, fracture and macroscopic flow behavior of polysynthetically twinned (PST) crystals of {gamma}/{alpha}{sub 2} TiAl-base alloys, an approach to achieve a good combination of strength, ductility and toughness in {gamma}/{alpha}{sub 2} TiAl-base alloys was proposed using directional solidification (DS) techniques to produce a columnar grain material with the lamellar orientation aligned parallel to the growth direction. Such alignment of the lamellar microstructure was recently accomplished in {gamma}/{alpha}{sub 2} TiAl-base alloys of near equiatomic compositions using an appropriately oriented seed crystal from the Ti-Al-Si system. At the same time, bi-PST crystals, each containing a planar boundary parallel to the loading axis were prepared by directional solidification and diffusion bonding of two PST crystals. Such bi-PST crystals were deformed in tension at room temperature and their deformation behavior was examined in terms of the compatibility requirements imposed at the grain boundary and the interaction of the two component PST crystals. In this paper, (i) the current status of the DS processing efforts, (ii) some result of microscopic characterization of grain boundaries in diffusion bonded bi-PST crystals and (iii) results of deformation experiments of bi-PST crystals prepared by DS processing and diffusion bonding, will be reported.

• Sponsoring Organization: New Energy and Industrial Technology Development Organization, Tokyo (Japan)
• OSTI ID: 571703
• Report Number(s): CONF-961202--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
DEFORMATION
EXPERIMENTAL DATA
GRAIN BOUNDARIES
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
SOLIDIFICATION
TITANIUM ALLOYS
TWINNING