The influence of solid solutions on flow behavior in {gamma}-TiAl

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20001577

Woodward, C; Kajihara, S A; Rao, S I; Dimiduk, D M

Modifications of alloy chemistry are often used to tailor the intrinsic flow behavior of structural materials. Models of solution strengthening, high temperature yield stress and creep must relate the effects of chemistry to the mechanisms that influence these material properties. In ordered alloys, additional information regarding the crystallographic site occupancy of ternary elements is required. In this study relaxed structures and energies for intrinsic and substitutional point defects are calculated using a first principles plane-wave-pseudopotential method. Calculated defect energies are used to predict the density and site preferences of solid-solutions (Si, Cr, Nb, Mo, Ta and W) in {gamma}-TiAl. Size and modulus misfit parameters are calculated and the interaction of these defects with a dissociated ordinary screw dislocation evaluated within anisotropic elasticity theory. The derived interaction strength is then related to solid-solution strengthening for these defect centers. Predicted solid-solution effects are in good agreement with experimental observations for the binary alloy.

• Research Organization: Air Force Research Lab., Wright Patterson AFB, OH (US)
• Sponsoring Organization: US Department of the Air Force
• OSTI ID: 20001577
• Report Number(s): CONF-981104--; ISBN 1-55899-458-0; ISSN 1067-9995
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
DEFORMATION
DISLOCATIONS
INTERSTITIALS
MATHEMATICAL MODELS
QUANTUM MECHANICS
SOLID SOLUTIONS
THEORETICAL DATA
TITANIUM ALLOYS