Microstructure Dependence of Compactibility of Rapidly Solidified Ti-Rich TiAl Alloy Powders Produced by Plasma Rotating Electrode Process

• Nishida Minoru

  Department of Materials Science, Kumamoto University

• Morizono Yasuhiro

  Department of Materials Science, Kumamoto University

• Kai Tomoaki

  Department of Materials Science, Kumamoto University

• Sugimoto Jun

  Department of Materials Science, Kumamoto University

• Chiba Akira

  Department of Materials Science, Kumamoto University

• Kumagae Ryohei

  Fukuda Metal Foil and Powder Co., Ltd.

書誌事項

タイトル別名

• Microstructure Dependence of Compactibi

抄録

The effect of initial microstructure on the compactibility at elevated temperatures in rapidly solidified Ti-rich TiAl alloy powders produced by the plasma rotating electrode process (PREP) has been investigated. There are two kinds of powders with respect to the microstructure. The first one has a surface relief of a martensitic phase and consists of twin-related α₂(Ti₃Al) lath platelets, which is referred to as M powder. The second one has a dendritic structure and consists of a single phase of α₂ with no microstructure other than the grain boundary, which is referred to as D powder. α₂+γ (TiAl) microduplex and α₂⁄γ lamellar structures are formed in M and D powders of the Ti-40 at%Al alloy by heat treatment at 1273 K, respectively. The microduplex structure consists of γ precipitate in the twin-related α₂ matrix with the usual orientation relationship. It is difficult to compact the D powder by hot pressing at 1273 K under 50 MPa for 14.4 ks. On the other hand, the M powder is compacted easily by hot pressing with the same condition. The twin-related α₂ and α₂ boundary changes to random ones and the α₂ and γ phases lose the usual orientation relationship in the duplex structure during the hot pressing. In other words, the low energy boundaries are changed to the high energy ones suitable for grain boundary sliding. Dislocations are scarcely observed inside of both the α₂ and γ crystal grains. It is concluded that the grain boundary sliding is a predominant deformation mode in the M powder during the hot pressing. The D and M powders in Ti-45 and 47 at%Al alloys show the same tendency as those in Ti-40 at%Al alloy during hot pressing. From the practical viewpoint the optimization of PREP conditions is also discussed to increase the number fraction of the M powder.

収録刊行物

• Materials Transactions, JIM

  Materials Transactions, JIM 38 (4), 334-343, 1997

  社団法人 日本金属学会

キーワード

• TiAl
• intermetallic compound
• rapidly solidified powder
• plasma rotating electrode process
• compactibility
• nonequilibrium phase
• α<SUB>2</SUB> martensite
• microduplex structure
• grain boundary sliding

詳細情報

• CRID: 1390001204247215360
• NII論文ID: 130003556919
• NII論文ID: 10002452352
• NII書誌ID: AA10699969
• DOI: 10.2320/matertrans1989.38.334
• COI: 1:CAS:528:DyaK2sXjvVamtro%3D
• ISSN: 2432471X
• ISSN: 09161821
• NDL書誌ID: 4209553
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4209553
• Web Site: https://www.jstage.jst.go.jp/article/matertrans1989/38/4/38_4_334/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可