Deformation and fracture behavior in TiAl alloys under monotonic and cyclic loading conditions

Book · Wed Dec 31 04:00:00 EST 1997

OSTI ID:293141

Kim, Y W ^[1]; Dimiduk, D M ^[2]

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1. UES, Inc., Dayton, OH (United States)
2. Wright Lab., Wright-Patterson AFB, OH (United States). Materials Directorate

Deformation and fracture behavior of two-phase TiAl alloys was investigated under monotonic as well as cyclic tension loading conditions for duplex and lamellar microstructural forms. The Hall-Perch relationship with an abnormally high constant in fully-lamellar material is explained as a combined function of grain-size and deformation-anisotropy characteristic of the lamellar structure. The effects of microstructure on the behavior are compared and analyzed for deformation temperatures below and above the brittle-ductile transition (BDT). The crack initiation toughness and associated strains near the crack tip are used to explain the inverse relationship between ductility and toughness observed at RT. The effect of temperature on the transition of cleavage-type transgranular fracture to intergranular and/or interlamellar fracture is discussed, along with the boundary weakening which is enhanced with increasing strain rate. The competition between the effects of grain size, lamellar spacing and plastic zone size on tensile and toughness properties is discussed.

• OSTI ID: 293141
• Report Number(s): CONF-970980--; ISBN 0-87339-381-3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
BRITTLE-DUCTILE TRANSITIONS
CRACK PROPAGATION
DEFORMATION
EXPERIMENTAL DATA
FRACTURE PROPERTIES
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
TENSILE PROPERTIES
TITANIUM ALLOYS