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First-principles based computational framework for the thermal conductivity of complex intermetallics: The case study of MgZn2 and Mg4Zn7.
- Source :
- Journal of Applied Physics; 1/7/2023, Vol. 133 Issue 1, p1-11, 11p
- Publication Year :
- 2023
-
Abstract
- Complex intermetallics usually exist as second phases in metal alloys. How these second phases can affect the thermal conductivity of alloys is generally unknown because the intrinsic thermal transport properties of these complex intermetallic compounds are quite less explored. In this work, we propose a computational framework based on first-principles calculations to study the electron and phonon thermal transport in complex intermetallics. Two typical intermetallics, i.e., MgZn<subscript>2</subscript> and Mg<subscript>4</subscript>Zn<subscript>7</subscript>, are studied as prototypes. The rigorous mode-level first-principles calculations are first carried out to study the thermal transport of MgZn<subscript>2</subscript>. The calculations not only provide accurate thermal conductivity results, but also allow to prove that the constant relaxation time approximation and the Slack model work quite well in complex intermetallics. Then these two models are combined with first-principles calculations to predict the thermal transport properties for Mg<subscript>4</subscript>Zn<subscript>7</subscript>. Our results show that the directional average thermal conductivities for MgZn<subscript>2</subscript> and Mg<subscript>4</subscript>Zn<subscript>7</subscript> are 53.9 and 21.9 W/mK, significantly smaller than those of their elemental counterparts. Electrons are found to be the main heat carriers in these compounds, leading to a nearly temperature-independent thermal conductivity. Phonon thermal conductivity is negligible due to large unit cells and weak metallic bondings. Our work provides reliable thermal conductivity values for MgZn<subscript>2</subscript> and Mg<subscript>4</subscript>Zn<subscript>7</subscript>. The computational framework developed in this work can also be further extended to study the electrical and thermal transport of other complex intermetallics. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00218979
- Volume :
- 133
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Journal of Applied Physics
- Publication Type :
- Academic Journal
- Accession number :
- 161194244
- Full Text :
- https://doi.org/10.1063/5.0125676