STUDIES ON THE DEFORMATION-BEHAVIOR OF INTERFACES IN (GAMMA+ALPHA-2) TITANIUM ALUMINIDE BY HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY

被引:52
作者
SINGH, SR
HOWE, JM
机构
[1] Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA
关键词
D O I
10.1080/09500839208207541
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The deformation behaviour of two-phase (gamma + alpha-2) titanium aluminide was investigated by high-resolution transmission electron microscopy. Specimens were deformed in compression at room temperature well beyond the yield point. The alpha-2-Ti3Al lamellae within the gamma-TiAl matrix were observed to deform by shearing when intersected by twins. In addition to dislocation slip, plastic deformation in gamma-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 gamma-alpha-2 interface. These observations and deformation mechanisms are discussed in terms of the structure of gamma-alpha-2 and twin interfaces.
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页码:233 / 241
页数:9
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