Interaction between deformation process and lamellar interfaces in polysynthetically twinned (PST) crystals of TiAl
- Shanghai Jiao Tong Univ. (China). Dept. of Materials Science and Engineering
Interaction of deformation process with lamellar interfaces was investigated by TEM observation. The {alpha}{sub 2}/{gamma} interfaces severely inhibit the deformation twin propagation. Even the {l_angle}11{bar 2}0{r_angle}{l_brace}0001{r_brace} slip mode can be activated in {alpha}{sub 2} lamellae, since not enough slip systems especially in [0001] direction are available, high local stress concentration is induced in the interfaces and {alpha}{sub 2} lamellae. The switch effect of deformation twinning to dislocation gliding at the interfaces between {gamma}-phase variants related by pseudo twin and 120{degree} rotational type are observed, which results from the interfaces inhibiting twin propagation and relaxing the stress concentration by emitting dislocations. Comparatively, the true twin interfaces have less resistance on deformation process, even twin dislocations and gliding dislocations pile up at the interfaces as deformation twins and gliding dislocations pass through them. Generally speaking, four kinds of interfaces have a resistance to deformation process in varying degrees and induce local stress concentration, which may play an important role on microcrack nucleation at the lamellar interfaces.
- OSTI ID:
- 225104
- Report Number(s):
- CONF-950201--; ISBN 0-87339-304-X
- Country of Publication:
- United States
- Language:
- English
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