Effect of vacancy, self-interstitial atoms and transmutation rhenium on lattice thermal conductivity in tungsten

Tungsten (W) is a promising candidate for plasma-facing components (PFCs) because of its excellent properties, such as a high melting point and high thermal conductivity (TC). However, neutron irradiation introduces lattice defects and transmutation, leading to the degradation of material properties. In this study, the reduction of lattice thermal conductivity (LTC) in W caused by point defects, such as vacancies, self-interstitial atoms, substitutional rhenium (Re) and interstitial Re were calculated using molecular dynamics at 300 K and 800 K using equilibrium molecular dynamics (EMD). Also, we calculate phonon density of state (DOS) and discuss how the point defects change the phonon DOS of crystalline W. It was found that interstitial Re decreased LTC most significantly, followed by random self-interstitial atoms, vacancies, and substitutional Re. Additionally, it was found that the calculation results of the phonon-phonon scattering rate by EMD deviate significantly from those by the ab initio method.