Molecular Dynamics Study On Mechanical Properties Of Crystalline Co Sb3 With Nanopores

Thermoelectric material is a kind of new functional material, which can achieve direct conversion between heat and electricity through the Seebeck effect. Thermoelectric devices are green, safe, and reliable, which has broad application prospects. Skutterudites based on CoSb3 thermoelectric material is attached great importance to the study of thermoelectric materials in our country and the international community. Inserting nanopores into skutterudite CoSb3 can remarkably reduce the thermal conductivity and improve the thermoelectric property, hence nanopourous CoSb3 is recognized as one of the most prospective thermoelectric materials. However, the nanopre in the CoSb3 will reduce the mechanical properties, which limits the application of thermoelectric materials in some important areas.Based on nanoporous CoSb3 thermoelectric material, this paper developed the molecular dynamics method to study the unixal tensile and compressive mechanical properties using our previous established interatomic potential. This paper aimed to study the influence of nanoporous shape and porosity on intrinsic mechanical behavior along unixal tension and compression and to reveal the structural fracture mechanism of nanoporous CoSb3 on the atomic scale. Moreover, the relationship between the porosity, nanoporous shape, and nanoporous distribution was explored. This paper will provide theoretical guidance for developing nanoporous CoSb3 with high mechanics.The mechanical behavior results of cylindrical nanoporous CoSb3 showed that the external conditions such as the temperature and the strain rate has little influence on the mechanical behavior, but the porosity has large influence on tensile/compressive mechanical behavior. Compared with the temperature and the porosity, cylindrical nanopores dominate the defect. With the increasing porosity, the mechanical behavior of nanoporous CoSb3 decreases gradually. The relationship between the elastic modulus and the porosity leads to a scaling law. The fracture strain linearly decreases with the increasing porosity.The mechanical behavior results of spherical nanoporous CoSb3 showed the mechanical behavior of spherical nanopores was much better than that of cylindrical nanopores, which can be attribute to the much more stress concentration areas in cylindrical nanoporous CoSb3. With the increasing porosity, all the mechanical quantities decrease gradually. The spherical nanoporous CoSb3 showed the same temperature softing effect. This effect is intensified with the increasing strain. The strain rate has little effect on the tensile/compressive elastic modulus and ultimate stress of spherical nanoporous CoSb3.