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Nucleation and Propagation of Deformation Twin in Polysynthetically Twinned TiAl

L. G. Zhou1, L. M. Hsiung2, Hanchen Huang1
Department of Mechanical, Aerospace & Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
Lawrence Livermore National Laboratory, Chemistry and Materials Science Directorate, P.O. Box 808, L-352, Livermore, CA 94551, USA

Computer Modeling in Engineering & Sciences 2004, 6(3), 245-252. https://doi.org/10.3970/cmes.2004.006.245

Abstract

Using molecular dynamics simulations, we study the deformation of polysynthetically twinned (PST) TiAl at room temperature. The simulation cell is pre-strained and thermodynamically relaxed to zero stress, so that no dislocations pre-exist in γ−α2 interfaces. A uniaxial compression is then applied along one 1/6<112] direction. Our results show that interfacial dislocation pairs nucleate at the γ−α2 interface under the compression. The glide and agglomeration of these dislocations lead to the nucleation of deformation twins from the interface. Based on our studies, twins may nucleate without pre-existing interfacial dislocations. Further we have monitored the propagation of the deformation twin, specifically its interaction with γ−γ and γ−α2 interfaces. The observations show that γ−α2 interfaces are stronger obstacles to the twin propagation than γ−γ interfaces are.

Keywords

TiAl, twin, dislocation, interface, molecular dynamics.

Cite This Article

Zhou, L. G., Hsiung, L. M., Huang, H. (2004). Nucleation and Propagation of Deformation Twin in Polysynthetically Twinned TiAl. CMES-Computer Modeling in Engineering & Sciences, 6(3), 245–252.



This work is licensed under a Creative Commons Attribution 4.0 International License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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