Effect of Al Content and Cooling Rate on Thermal Stability of Fully Lamellar Microstructures in TiAl Alloys

LI Zhen-xi; QI Li-chun; HUANG Xu; CAO Chun-xiao

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Journal of Aeronautical Materials ›› 2006, Vol. 26 ›› Issue (3) : 66-70.

Effect of Al Content and Cooling Rate on Thermal Stability of Fully Lamellar Microstructures in TiAl Alloys

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Abstract

The effects of Al content and continuous cooling rate on thermal stability of fully lamellar(FL) microstructure in TiAl alloys at 1150℃ were investigated.For the binary TiAl alloys with 46at%~48at%Al,the higher the Al content is,the more serious the γ dendritic segregation is and the less stable of as-cast FL microstructure is.The thermal stability of coarse lamellar microstructure in Ti-48Al alloy formed by furnace cooling from the α single phase field is superior to that of fine lamellar microstructure formed by air cooling.For the fine lamellar microstructure,the lamellar discontinuous coarsening occured at the grain boundaries,meanwhile the interfaces between the Widmnstatten lamellar colonies within the grains and the lamellar matrix also become the original sites of discontinuous coarsening.

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TiAl alloy / fully lamellar micro / thermal stability / discontinuous coarse

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LI Zhen-xi, QI Li-chun, HUANG Xu, CAO Chun-xiao. Effect of Al Content and Cooling Rate on Thermal Stability of Fully Lamellar Microstructures in TiAl Alloys[J]. Journal of Aeronautical Materials, 2006, 26(3): 66-70

References

KIM Y W.Effects of microstructure on the deformation and fracture of γ-TiAl alloys[J].Mater Sci Eng,1995,192/193A:519-533.
KIM Y W,DIMIDUK M.Designing gamma TiAl alloys:Fundametals,Strategy and Production[A].In:NATHAL M V,ed.Structure Intermetallics 1997[C].TMS,Warrardale,PA,1997.531-543.
BARTHOLOMEUSZ M F,WERT J A.Modeling creep deformation of a two-phase TiAl/Ti3 Al alloy with a lamellar microstructure[J].Metall Mater Trans,1994,25A (6):2161-2172.
BEDDOES J.Structural Intermetallic[A].DAROLIA R,ed.[C].TMS,Warrendale,PA,1997.109-118.
RAMANUJAN R V,MAZIASZ P J,LIU C T.The thermal stability of the microstructure of γ-based titanium aluminides[J].Acta mater,1996,44 (7):2611-2642.
MITAO S,BENDERSKY L A.Coarsening behavior of lamellars structure in Ti-(40-47)Al(at.%) alloy[A] In:KIM Y W,ed.Gamma Titanium Aluminides[C].TMS,Warrendale,PA,1995.181-188.
SHONG D S,KIM Y W.Discontinuous coarsening of high perfection lamellae in titanium aluminides[J].Scripta metall,1989,23 (2):257-26 1.
MITAO S,BENDERSKY L A.Morphology and growth kinetics of discontiuous coarsening in fully lamellar Ti-44Alalloy[J].Acta mater,1997,45 (11):4475-4489.
QIN G W,WANG J,HAO S M.Discontnuous coarsening of primary α2/γ lamellae at colony boundaries in g-TiAlbasred alloys[J].Intermetallics,1999,7 (1):1-4.
HUANG S C,SIEMERS P A.Characterization of the High-Temperature Phase fields near Stoichiometric γ-TiAl[J].Metall Trans,1989,20A (10):1899-1906.
KATTNER U R,LIN J C,CHANG Y A.Thermodynamic Assessment and Calculation of Ti-Al System[J].Metall Trans,1992,23A(8):2081-2090.
CLINE H E.Shape instabilities of eutectic composites at elevated temperatures[J].Acta metall,1971,19 (6):481-490.
LIVINGSTON J D,CAHN J W.Discontinuous coarsening of aligned eutectoids[J].Acta metall,1974,22 (4):495-503.