Highly fluidic liquid at homointerface generates grain-boundary dislocation arrays for high-performance bulk thermoelectrics
- Authors
- 문현아; 이규형; 유승조; 김현식; 정지원; 오상호; G. J. Snyder; 김영희; 김영민; 김성웅
- Issue Date
- Oct-2018
- Publisher
- PERGAMON-ELSEVIER SCIENCE LTD
- Citation
- ACTA MATERIALIA, v.159, no.-, pp.266 - 275
- Journal Title
- ACTA MATERIALIA
- Volume
- 159
- Number
- -
- Start Page
- 266
- End Page
- 275
- URI
- https://scholarworks.bwise.kr/hongik/handle/2020.sw.hongik/3171
- ISSN
- 1359-6454
- Abstract
- Dislocation arrays embedded in low-angle grain-boundaries have emerged as an effective structural defect for a dramatic improvement of thermoelectric performance by reducing thermal conductivity [1] A transient liquid-flow assisted compacting process has been employed for p-type Bi0.5Sb1.5Te3 material to generate the dislocation arrays at grain-boundaries. The details of underlying formation mechanism are crucial for the feasibility of the process on other state-of-the-art thermoelectric materials but have not been well understood. Here, we report the direct observation of dislocation formation process at grain-boundaries of Sb2Te3 system as a proof-of-concept material. We found that the formation of homointerface between Te-terminated Sb2Te3 matrix phase and Te liquid atomic-layer of secondary phase is a prerequisite factor to achieve the low-energy liquid-solid homointerface at compacting elevated temperature. We further demonstrate from the successful observations of atomic structure in the intermediate state of the compacted pellet that the high self-diffusion rate of Te atoms at the liquid-solid homointerface facilitates an effective grain rearrangement, generating low-energy grain-boundaries embedded with dense dislocation arrays. These results pave the way to improve thermoelectric performance of various materials where dislocation arrays are generated by transient liquid-flow assisted compacting process using precursors with an interface constructed with the same types of atoms. (C) 2018 Published by Elsevier Ltd on behalf of Acta Materialia Inc.
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Collections - Graduate School > Materials Science and Engineering > 1. Journal Articles
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