Point defect engineering and machinability in n-type Mg3Sb2-based materials

Li, Juan and Zhang, Shuai and Jia, Fei and Zheng, Shuqi and Shi, Xiaolei ORCID: https://orcid.org/0000-0003-0905-2547 and Jiang, Daqiang and Wang, Siyu and Lu, Guiwu and Wu, Liming and Chen, Zhi-Gang ORCID: https://orcid.org/0000-0002-9309-7993 (2020) Point defect engineering and machinability in n-type Mg3Sb2-based materials. Materials Today Physics, 15:100269. pp. 1-8. ISSN 2542-5293


Abstract

Approaching practical thermoelectric devices require high-performance and machinable thermoelectric materials. However, the currently available materials are usually brittle. In this work, Nd-doped Mg3Sb2-based compounds exhibit not only excellent thermoelectric performance but also superior machinability. Mg3.2Nd0.03Sb1.5Bi0.5 exhibits a high power factor of 20.6 μW cm-1 K-2 at 725 K and a peak zT of 1.8, which mainly originates from the increased n of ∼8 × 1019 cm-3 by Nd/Mg substitutional defects. Defect calculations predict that other rare earth elements (Sm, Gd, Tb, Dy and Ho) have the same effect as Nd on Mg3Sb2 and the predicted highest achievable electron concentrations at 700 K are ∼1020 cm-3. The measured hardness, Young’s modulus and fracture toughness of Mg3.2Nd0.03Sb1.5Bi0.5 are 1.1 GPa, 49.8 GPa and 1.4 MPa m1/2, respectively. In addition, the sample can be easily machined into the dog-bone shape with external thread at both ends, indicating the excellent machinability of Mg3Sb2-based materials. This work suggests a bright future of Mg3Sb2-based thermoelectric materials for practical applications and device fabrication.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Date Deposited: 10 Sep 2020 03:20
Last Modified: 23 Apr 2021 03:57
Uncontrolled Keywords: Mg3Sb2; machinability; defect engineering; thermoelectrics
Fields of Research (2008): 09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Identification Number or DOI: https://doi.org/10.1016/j.mtphys.2020.100269
URI: http://eprints.usq.edu.au/id/eprint/39437

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