Thermodynamic and mechanical properties of crystalline CoSb3: A molecular dynamics simulation study

Abstract

Molecular dynamics simulations have been performed to study the fundamental thermodynamic and mechanical properties of single-crystalline skutterudite CoSb3 in the nanometric scale. The several interesting thermodynamic predictions, including linear thermal expansion coefficient, specific heat capacity, thermal conductivity, and temperature dependence of elastic constants, show excellent agreement with data available in the literature. The classic mechanical tests of uniaxial tension and compression are performed respectively at constant temperatures. The CoSb3 single-crystal exhibits nonlinear elastic response during the deformation process and the sustainable stress is very high, demonstrating its outstanding stability. An interesting phenomenon occurs at compression that the stress-strain curve undergoes a transition. The cause of the transition is an atomic reconstruction, which is observed and interpreted on the basis of interatomic interactions. Both of the failure patterns under tension and compression reveal brittleness of the material. The increasing of temperature would result in a linear degradation of the effective Young’s modulus and ultimate strength, but its effect on Poisson’s ratio is negligible. The results provide the groundwork for future studies of service behavior of the skutterudites-based thermoelectric devices.

Fabrication and reliability evaluation of Yb0.3Co4Sb12/Mo–Ti/Mo–Cu/Ni thermoelectric joints

“…Besides high ZT value, SKD also exhibits good mechanical properties over a temperature range from 200 1C to 500 1C [10][11][12]. In recent years, some research has been conducted in SKD-based TE devices.…”

Influence of the substrate thermal expansion coefficient on the morphology and elastic stress of CoSb3 thin films

“…The corresponding interplanar distances were calculated, showing a linear dependence on sin 2 ψ , which justifies the use of a biaxial stress model and confirms the absence of shear stress contributions. Therefore, one can calculate the film stress using the bulk values of CoSb 3 for the isotropic Young's modulus ( E F = 160 GPa) and the Poisson ratio ( v = 0.193) 27. The calculated residual stress values as a function of the thermal expansion coefficient are shown in Fig.…”

Influence of Nanopores on the Tensile/Compressive Mechanical Behavior of Crystalline CoSb3: A Molecular Dynamics Study

“…The transition pattern at 12% strain of the ideal bulk can be attributed to the cubic Co frame change during the compressive process, as shown in Ref. 18. Before the cubic Co frame changes, the Sb4 rings changes from rectangle to rhomboid under the compressive strain.…”