Atomistic details in defect evolution 

in W under neutron irradiation unveiled

Prof. Keonwook Kang and his research team published an original article, "Free-surface effect on displacement cascades in BCC W: molecular dynamics study", in Nuclear fusion (IF: 3.706, JCR top 8.82%). This paper investigates defect formation and growth mechanisms near the tungsten surface under neutron irradiation using molecular dynamics simulation. Increased interstitial mobility near the surface suppresses defect recombination events and promotes formation of extended defects such as dislocation via vacancy clustering. Theses vacancy loops can develop into a micro-void or act as a source of crack, which triggers catastrophic brittle fracture. This study identifies the origin of extreme brittle behavior of W and has significant applications for designing W and its alloys as facing materials in nuclear fusion environment.