Microstructural effects on creep properties of a Ti-48Al alloy

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:225170

Viswanathan, G B; Vasudevan, V K ^[1]

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1. Univ. of Cincinnati, OH (United States). Dept. of Materials Science and Engineering

Creep properties of a Ti-48Al alloy with the near gamma, duplex and fully lamellar microstructures are reported at temperatures between 700--815 C and stresses between 103--240 MPa. Microstructure is observed to exert a strong influence on the creep behavior, with the fully lamellar structure exhibiting the lowest minimum creep rate, followed in increasing order by the duplex and near gamma structures. Activation energies of 310/336 kJ/mole and stress exponents of 5.5/5.0 are obtained for the near gamma/duplex structures, respectively. These values, together with observed dislocation structures, are consistent with a climb controlled dislocation power law creep mechanism. In the case of the fully lamellar microstructure, while the activation energy value obtained (350kJ/mole) is similar to those of the near gamma/duplex structures, a change in the stress exponent from {approximately}3.0 at low stresses to {approximately}8.0 at high stresses is observed, which suggests a change in the creep mechanism. These results are presented and rationalized in terms of microstructural features, particularly grain size and characteristics of the lamellar constituent.

• OSTI ID: 225170
• Report Number(s): CONF-950201--; ISBN 0-87339-304-X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
ALUMINIUM ALLOYS
CREEP
DISLOCATIONS
EXPERIMENTAL DATA
EXTRUSION
GRAIN SIZE
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
LAMELLAE
MICROSTRUCTURE
OPTICAL MICROSCOPY
SAMPLE PREPARATION
SCANNING ELECTRON MICROSCOPY
STRAINS
STRESSES
TEMPERATURE DEPENDENCE
TITANIUM ALLOYS
TRANSMISSION ELECTRON MICROSCOPY