Phase Transitions and Their Interaction with Dislocations in Silicon

Date
2018-01-01
Authors
Levitas, Valery
Chen, Hao
Xiong, Liming
Levitas, Valery
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Aerospace Engineering
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Ames Laboratory
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Mechanical Engineering
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Aerospace EngineeringAmes LaboratoryMechanical EngineeringMaterials Science and Engineering
Abstract

In this paper, phase transformations (PTs) in silicon were investigated through molecular dynamics (MD) using Tersoff potential. In the first step, simulations of PTs in single crystal silicon under various stress-controlled loading were carried out. Results shows that all instability points under various stress states are described by criteria, which are linear in the space of normal stresses. There is a region in the stress space in which conditions for direct and reverse PTs coincide and a unique homogeneous phase transition (without nucleation) can be realized. Finally, phase transition in bi-crystalline silicon with a dislocation pileup along the grain boundary (GB) was carried out. Results showed that the phase transition pressure first decreases linearly with the number of dislocation pileups and then reaches a plateau with the accumulation of dislocations in the pileup. The maximum reduction of phase transition pressure is 30% compared to that for perfect single crystalline silicon.

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This is a post-peer-review, pre-copyedit version of an article published as Levitas, Valery I., Hao Chen, and Liming Xiong. "Phase transitions and their interaction with dislocations in silicon." In Proceedings of the International Conference on Martensitic Transformations: Chicago, edited by A. Stebner and G. Olson. Springer, Cham, 2018: 83-87. DOI: 10.1007/978-3-319-76968-4_13. Posted with permission.

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