Thermal Conductivity Of Al-based Quasicrystal Related Systems:Molecular Dynamics Simulations

As a new material, the quasicrystal has shown many excellent properties, such as unique heat transfer. Compared with common metallic materials, quasicrystals have very low thermal conductivity, which is about two orders of magnitude lower than that of normal aluminum alloy at room temperature, and is equivalent to that of typic insulating materials, ZrO2. A large number of stable and metastable quasicrystals exist in binary and ternary Al alloy system, achieving great interests in both theoretical and experimental works.Using molecular dynamic simulations, we investigated the size and temperature effect on the thermal conductivity in Al-based quasicrystal related materials. Lammps, as one successful molecular dynamic simulation software, has been adopted to fulfill the computations efficiently.Firstly, we used equilibrium molecular dynamics method to study the thermal conductivity of the structure tI6 and oF24 structures in Al-Fe system. The simulation results showed that the thermal conductivity of t I6 and oF24 both increased with the increasing of the supercell size, before convergence. When the temperature increases from100 K to 1000 K, the thermal conductivity of tI6 decreases continuously.Secondly, we studied the thermal conductivity of Al-Ir with clathrate structure. The result revel that the thermal conductivity of oP60 increases with the increasing of the supercell size. When the temperature increasing from 100 K to 500 K, the thermal conductivity also increases.Finally, we studied the size and temperature effect of the thermal conductivity relating to several quasicrystal approximation phases of Al-Pd-Mn system by choosing the EAM potential and using equilibrium molecular dynamics method.