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Molecular Dynamics Simulation of the Structure and Deformation Behavior of γ/α2 Interface in TiAl Alloys |
Aidong TU1,2, Chunyu TENG3, Hao WANG1(), Dongsheng XU1, Yun FU3, Zhanyong REN3, Rui YANG1 |
1 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China 2 School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China 3 Laboratory of Fundamental Research, AVIC China Aero-Polytechnology Establishment, Beijing 100028, China |
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Cite this article:
Aidong TU, Chunyu TENG, Hao WANG, Dongsheng XU, Yun FU, Zhanyong REN, Rui YANG. Molecular Dynamics Simulation of the Structure and Deformation Behavior of γ/α2 Interface in TiAl Alloys. Acta Metall Sin, 2019, 55(2): 291-298.
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Abstract TiAl alloys with γ-TiAl and α2-Ti3Al dual-phase lamellar structure possess not only excellent high temperature performance but also density only about half of traditional superalloys. Such lamellar structure largely determines the mechanical properties of TiAl alloys. However, there is still a lack of understanding on the atomic structure of lamella, as well as their influence on the mechanical behaviors. For this reason, molecular dynamics with an embedded-atom potential is employed to investigate the energies of both the coherent and semi-coherent γ/α2 interfaces. The interface coherency is found to depend on the thickness ratio of γ lamellae to α2 lamellae, and there exists a critical lamella thickness, below/above which the interface is coherent/semi-coherent. Tensile loading perpendicular to the lamella interface indicates that the yield strength of coherent interface is higher than that of semi-coherent interface and the crack nucleation behavior varies with the thickness ratio of γ lamellae to α2 lamellae. The plastic deformation occurs first in the γ region, forming Shockley partial dislocations and then crosses the γ/α2 interface via slip transfer, activating stacking faults on the pyramidal plane in the α2 region. In this process, the γ/α2 interface provides nucleation sites for subsequent dislocations and cracks.
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Received: 07 May 2018
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Fund: Supported by National Key Research and Development Program of China (No.2016YFB0701304), National Natural Science Foundation of China (No.51671195), Aeronautical Science Foundation of China (No.20160292002), Youth Innovation Promotion Association of Chinese Academy of Sciences (No.2015151) and Special Project on Information Technology of Chinese Academy of Sciences (No.XXH13506-304) |
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