Grain boundary segregation mediated highly stable and high performance nanostructured MgAgSb bulk thermoelectric materials

Transactions of Materials Research, vol. 1, pp. 100016

Abstract

We systematically elaborate the thermal stability mechanism of MgAgSb-based materials through thermodynamic and kinetic analysis of grain boundary characterizations. By proposing the general strategy of grain boundary segregation engineering (GBSE) to improve the stability of nanostructured bulk thermoelectric materials , it is found that excessive Cu doping can modify the microstructure to enhance stability as both Ag and Cu segregation coexist at the grain boundary. After annealing at elevated temperature, the final performance is almost unchanged with a high room-temperature dimensionless figure-of-merit zT of around 0.7, in contrast to property deterioration of pure MgAgSb. As revealed by atom probe tomography (APT) measurements, Cu segregation inhibits grain boundary migration and hinders grain growth, due to the additional reduced grain boundary energy and mobility. Our work provides new insights into the critical role of grain boundary segregation in the properties optimization and thermal stability enhancement, which opens up alternative perspectives for designs of highly stable and high-performance nanostructured thermoelectric materials .

Authors 11

1. Liangjun Xie

   Harbin Institute of Technology

   Affiliation as printed

   National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001, China

2. Yuke Zhu

   Harbin Institute of Technology

   Affiliation as printed

   National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001, China

   State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China

3. Lankun Wang

   Harbin Institute of Technology

   Affiliation as printed

   State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China

4. Yuxin Sun

   Harbin Institute of Technology

   Affiliation as printed

   National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001, China

5. Yuan Yu Aachen Institute of Physics (IA)

   RWTH Aachen University

   Affiliation as printed

   Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, Aachen, 52074, Germany

6. A.B. Ivanova

   National University of Science and Technology

   Affiliation as printed

   National University of Science and Technology (NUST MISIS), Moscow, 119049, Russia

7. Vladimir V. Khovaylo

   National University of Science and Technology

   Affiliation as printed

   National University of Science and Technology (NUST MISIS), Moscow, 119049, Russia

8. Fengkai Guo

   Harbin Institute of Technology

   Affiliation as printed

   National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001, China

9. Wei Hua Cai

   Harbin Institute of Technology

   Affiliation as printed

   National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001, China

10. Jiehe Sui

    Harbin Institute of Technology

    Affiliation as printed

    National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001, China

11. Zihang Liu corresponding

    Harbin Institute of Technology

    Affiliation as printed

    State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin, 150001, China