Effect of hydrostatic strain on the thermal conductivity of β-SiC: A combined molecular dynamics and lattice dynamics investigation

YH Wang and BQ Fu, JOURNAL OF MATERIALS RESEARCH, 38, 1634-1643 (2023).

DOI: 10.1557/s43578-023-00914-0

SiC is quite often used in a variety of industrial scenarios because of its superior mechanical and thermal properties. Strain in SiC materials is ubiquitous in industrial settings, and it affects the material's thermal conductivity. Non-equilibrium molecular dynamics and lattice dynamics from phonon perspectives were used to study the thermal conduction process of SiC under various strains (- 7% similar to + 7%). Our research demonstrates how strain affects beta-SiC's thermal conductivity. The thermal conductivity of SiC between - 7% and + 7% strain was determined using the spectral heat current method, and the effect of phonon frequencies on thermal conductivity was investigated. Lattice dynamics was also used to calculate the phonon dispersion relation, phonon group velocity, and phonon lifetime. These phonon properties were used to study thermal conductivity from the standpoint of phonon transport. Phonon lifetime first rises and reaches its maximum with an increase in compressive strain before falling off. Thermal conductivity decreases as a result of the phonon lifetime decreasing. Group velocity and phonon lifetime gradually decrease as tensile strain increases. The thermal conductivity falls as a result of both. Our findings enhance our knowledge of the thermal conduction mechanism in beta-SiC. These variations in thermal conductivity are brought on by phonon properties that change as a result of strain. This conclusion could be applied to a wide variety of other materials.

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