辐照损伤对钨晶格热导率影响的分子动力学研究.

Tungsten (W) has been considered as candidate plasma facing material (PFM) in nuclear fusion reactor. However, the severe work environment will cause radiation damage of W, which will affect its thermal energy transport. We constructed the structural model of undamaged and damaged W, and used the non-equilibrium molecular dynamics (NEMD) simulations to quantitatively study the thermal conductivity of W. The results show a decrease in lattice thermal conductivity with the increase of neutron radiation energy. Interstitial atoms trend to segregate at grain boundary, and the interstitial W atoms have a greater effect on lattice thermal conductivity than vacancies. Nanoscale-sized He bubbles cause a significant decrease in the lattice thermal conductivity of W, which down to - 25 % of its perfect crystal value when the porosity is 2.1%. These different defects cause different degrees of lattice deformation, which increase the phonon scattering and result in the decrease of lattice thermal conductivity. [ABSTRACT FROM AUTHOR]