Effects of long-period superstructures on plastic properties in Al-rich TiAl single crystals
- PDF / 1,424,574 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 76 Downloads / 222 Views
S7.4.1
Effects of long-period superstructures on plastic properties in Al-rich TiAl single crystals Takayoshi Nakano*), Koutaro Hayashi, Yukichi Umakoshi, Yu-Lung Chiu1) and Patrick Veyssière1) Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan 1 Laboratoire d’Etude des Microstructures, CNRS-ONERA, BP72, 92322 Châtillon cedex, France *) E-mail: [email protected] ABSTRACT In Al-rich TiAl crystals, several long-period superstructures may appear depending on Al composition, annealing temperature and annealing time. Amongst these, Al5Ti3 and h-Al2Ti contain pure Al (002) layers, as in the L10 structure of the matrix, alternating with Ti (002) layers that exhibit an ordered arrangement of the Al atoms in excess. In single crystals with compositions ranging from Ti-54.7at.%Al to Ti-62.5at.%Al annealed at 1200°C, the Al5Ti3 long-period superstructure embedded in the L10 matrix develops with increasing Al concentration to finally transform fully into h-Al2Ti for Ti-62.5at.%Al. On the other hand, Al5Ti3 precipitates grow with annealing time at 500°C in Ti-58.0at.%Al. The effects of the Al5Ti3 and h-Al2Ti superstructures on slip properties of 1/2
Data Loading...