Evolution of defects and deformation mechanisms in different tensile directions of solidified lamellar Ti-Al alloy |
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| Affiliation: | 1.Institute of New Optoelectronic Materials and Technology, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China;2.College of Computer Science and Electronic Engineering, Hunan University, Changsha 410082, China |
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| Abstract: | Two-phase γ-TiAl/α2-Ti3Al lamellar intermetallics have attracted considerable attention because of their excellent strength and plasticity. However, the exact deformation mechanisms remain to be investigated. In this paper, a solidified lamellar Ti-Al alloy with lamellar orientation at 0°, 17°, and 73° with respect to the loading direction was stretched by utilizing molecular dynamics (MD) simulations. The results show that the mechanical properties of the sample are considerably influenced by solidified defects and tensile directions. The structure deformation and fracture were primarily attributed to an intrinsic stacking fault (ISF) accompanied by the nucleated Shockley dislocation, and the adjacent extrinsic stacking fault (ESF) and ISF formed by solidification tend to form large HCP structures during the tensile process loading at 73°. Moreover, cleavage cracking easily occurs on the γ/α2 interface under tensile deformation. The fracture loading mechanism at 17° is grain boundary slide whereas, at 73° and 0°, the dislocation piles up to form a dislocation junction. |
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| Keywords: | molecular dynamics simulation solidified lamellar Ti-Al alloy tensile directions γ/α2 interface |
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