Epsilon and Eta Phases Precipitated in an Fe-38Ni-13Co-4.7Nb1.5Ti-0.4Si Superalloy.

• Kusabiraki Kiyoshi

  Faculty of Engineering, Toyama University

• Amada Eiji

  Graduate Student, Toyama University

• Ooka Takayuki

  Toyama University

• Saji Shigeoki

  Faculty of Engineering, Toyama University

Abstract

An Fe-38Ni-13Co-4.7Nb-1.5Ti-0.5Si alloy is a controlled low thermal expansion superalloy with a good resistance to SAGBO (Stress Accelerated Grain Boundary Oxidation) embrittlement at elevated temperatures by an intensional Si addition. The precipitation of second phases, ε phase, η phase and so on, in this superalloy is investigated by means of optical microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. A time-temperature-transformation diagram for the ε phase is presented.The crystal structure and the lattice parameters of the ε phase and the orientation relationship with the alloy matrix g are determined. It is shown that the η phase is not a stable phase as well as γ' phase, but cellular η phase is the most stable precipitation phase in this alloy.

Journal

• ISIJ International

  ISIJ International 37 (1), 80-86, 1997

  The Iron and Steel Institute of Japan

Keywords

• Incoloy 909
• iron base alloy
• superalloy
• precipitation
• ε phase
• crystal structure
• η phase

Details

• CRID: 1390001206452616448
• NII Article ID: 10002454791
• NII Book ID: AA10680712
• DOI: 10.2355/isijinternational.37.80
• COI: 1:CAS:528:DyaK2sXnsFOgtg%3D%3D
• ISSN: 13475460
• ISSN: 09151559
• Web Site: http://www.jstage.jst.go.jp/article/isijinternational1989/37/1/37_1_80/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed