Studies on the deformation behaviour of interfaces in (γ + α2) titanium aluminide by high-resolution transmission electron microscopy
作者:
S.R. Singh,
J.M. Howe,
期刊:
Philosophical Magazine Letters
(Taylor Available online 1992)
卷期:
Volume 65,
issue 5
页码: 233-241
ISSN:0950-0839
年代: 1992
DOI:10.1080/09500839208207541
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The deformation behaviour of two-phase (γ + α2) titanium aluminide was investigated by high-resolution transmission electron microscopy. Specimens were deformed in compression at room temperature well beyond the yield point. The α2-Ti3Al lamellae within the γ-TiAl matrix were observed to deform by shearing when intersected by twins. In addition to dislocation slip, plastic deformation in γ-TiAl was found to proceed by (a/6)<112] twinning partial dislocations, as revealed by the steps on twin interfaces, and by the creation of a three-plane (9R) deformation-induced structure parallel to pre-existing twin interfaces. Formation of the 9R structure is due to an antitwinning operation on every third plane. The core structure of (a/6)<112] twinning partial dislocation steps appears narrow compared with similar (a/6)<112] partial dislocations associated with growth ledges at the γ-α2interface. These observations and deformation mechanisms are discussed in terms of the structure of γ-α2and twin interfaces.
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