Effect of high fluence Au ion irradiation on nanocrystalline tungsten film

Irradiation-induced microstructure evolution and phase transformation have been studied on the nanocrystalline tungsten film with simple cubic structure (B phase). The samples were irradiated by 4 MeV Au ions at different fluences ranging from 6 x 10(14) to 1 x 10(16) ions/cm(2), corresponding to the peak damage levels from 6 to 100 dpa (displacements per atom). Analysis by GIXRD and TEM reveals that the structure of tungsten film undergoes a distinct transition from simple cubic phase to bcc phase when the fluence is above 3 x 10(15) ions/cm(2) (30 dpa) and grain growth occurs with the increasing fluence. Radiation-induced small voids are clearly observed in the interior of coarsened grains at the highest fluence, 1 x 10(16) ions/cm(2) (100 dpa). (C) 2013 Elsevier B.V. All rights reserved.Materials Science, MultidisciplinaryNuclear Science & TechnologyMining & Mineral ProcessingSCI(E)EI2ARTICLE1-3189-19444