Crystallographic aspects of deformation twinning and consequences for plastic deformation processes in {gamma}-TiAl

Journal Article · Fri Feb 25 04:00:00 EST 2000 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(99)00385-7· OSTI ID:20015586

Skrotzki, B

Mechanical twinning is an important deformation mechanism in the {gamma}-phase of near-{gamma}-TiAl alloys at room temperature as well as at high temperature. The present work examines the crystallography of twinning in the ordered L1{sub 0} structure of the {gamma}-phase and quantifies the resulting deformation for different crystallographic directions. In addition, the open question is addressed whether twin interfaces represent obstacles for glide dislocations. It is shown that one part of the possible glide dislocations remains completely unaffected by the twin interface because their Burgers vectors lie in the twin plane. The other part of the dislocations has to change its glide directions while passing the interface, which can occur by suitable dissociation processes. Prerequisite is a sufficiently high applied stress. The reoriented twin may be more favorably oriented for some glide directions than its parent crystal and thus promote further dislocation plasticity. The impact of this effect on ductility depends on the volume fraction of twins.

• Research Organization: Ruhr-Univ. Bochum (DE)
• OSTI ID: 20015586
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 4 Vol. 48; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CRYSTALLOGRAPHY
DEFORMATION
DISLOCATIONS
INTERFACES
INTERMETALLIC COMPOUNDS
TITANIUM ALLOYS
TWINNING