title: HRTEM image contrast and atomistic microstructures of long-period ordered Al-rich TiAl alloys.
abstract: Long-period superstructures formed in off-stoichiometric L 1(0)-TiAl alloys were investigated by high-resolution transmission electron microscopy (HRTEM). The HRTEM analysis combined with multislice simulation and image processing was carried out to clarify atomistic microstructures of Al5Ti3 and h-Al2Ti ordered states and a short-range ordered (SRO) state in Ti-62.5 at.% Al alloys. Aluminium atoms in the (002) Ti layers form square-, lean rhombus- and fat rhombus-type ordered clusters in the SRO state. The ordered clusters are in contact with each other and form microdomains of various long-period superstructures. The ordered clusters are tiled periodically in a long range to form Al5Ti3 or h-Al2Ti domains and characteristic antiphase boundary structures.
authors.affiliation: Department of Applied Science for Electronics and Materials, Kyushu University, Fukuoka 816-8580, Japan. hata@asem.kyushu-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hata
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Higuchi
authors.forename: Toshitsugu
authors.initials: T
authors.lastname: Mitate
authors.forename: Masaru
authors.initials: M
authors.lastname: Itakura
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Tomokiyo
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kuwano
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Nakano
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nagasawa
authors.forename: Yukichi
authors.initials: Y
authors.lastname: Umakoshi
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000535:Aluminum / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D008854:Microscopy, Electron; D015394:Molecular Structure; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D000535:Aluminum; D014025:Titanium