Atomistic simulation for strain effects on threshold displacement energies in refractory metals

Abstract

To evaluate the extent of radiation damage for specific materials, defect formation energies and threshold displacement energies (TDEs) are important quantities. In this work, we study the influence of hydrostatic and uniaxial strains on the Frenkel pair formation energy (FPE) and TDE for tungsten, molybdenum, and vanadium, which can be used in plasma devices and fusion reactors. With an applied tensile strain, the self-interstitial atom formation energy decreases significantly, while the vacancy formation energy slightly increases, which causes concurrent decreases in the FPE and TDE. The opposite responses are observed with an applied compression strain. This result indicates that radiation defect formation is enhanced by a tensile strain and suppressed by a compressive strain. The strain effects on the TDE and FPE are determined mainly by the volume change in the deformed crystal, regardless of the strain mode. Both the TDE and FPE under strain conditions are described by linear functions of the volume change.