Effect of composition and lamellar microstructure on creep properties of P/M near {gamma}-TiAl alloys
- Carleton Univ., Ottawa, Ontario (Canada). Dept. of Mechanical and Aerospace Engineering
- National Research Council Canada, Ottawa, Ontario (Canada)
Creep testing at 760 C/276 MPa of P/M Ti-48%Al, Ti-48%Al-3%Cr and Ti-48%Al-2%W heat treated to the fully transformed condition, reveals that the ternary element reduces the minimum creep strain rate, with W more effective than Cr. The stress exponent for TiAl+W, determined by stress increments at 760 C, increases from <1 at 172 MPa to {approx}8 at >300 MPa, indicating a transition in the mechanism controlling the minimum creep strain rate. Reducing the lamellar grain size of TiAl+W to {approx}200 {micro}m improves rupture life by increasing the extent of tertiary creep, which is accommodated by dynamic recrystallization of {gamma} along lamellar grain boundaries or extensive secondary cracking. Further modification of the TiAl+W lamellar structure achieved a creep life of >1,250 h and minimum strain rate of 2.8 {times} 10{sup {minus}5}h{sup {minus}1} at 760 C/276 MPa.
- OSTI ID:
- 225169
- Report Number(s):
- CONF-950201-; ISBN 0-87339-304-X; TRN: IM9621%%99
- Resource Relation:
- Conference: Annual meeting and exhibition of the Minerals, Metals and Materials Society (TMS), Las Vegas, NV (United States), 12-16 Feb 1995; Other Information: PBD: 1995; Related Information: Is Part Of Gamma titanium aluminides; Kim, Y.W. [ed.] [UES, Inc., Dayton, OH (United States). Materials and Processes Div.]; Wagner, R. [ed.] [GKSS Research Center, Geesthacht (Germany). Inst. for Materials Research]; Yamaguchi, Masaharu [ed.] [Kyoto Univ. (Japan). Dept. of Materials Science and Engineering]; PB: 1023 p.
- Country of Publication:
- United States
- Language:
- English
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