Period-thickness dependent responses of Cu/W multilayered nanofilms to ions irradiation under different ion energies

Nanostructured multilayers have been well proved to be highly tolerant to radiation comparing to traditional single-phase bulk materials, because the interfaces act as sinks to annihilate radiation-induced defects. The study on the response of same multilayered nanofilm to irradiation under different ion energies has not been reported. In this work, the immiscible Cu/W multilayered nanofilms with period-thicknesses of 6, 12, 18, and 24 nm were irradiated by ions at different energies (40 keV He+, 6.4 MeV Xe23+ and 200 MeV Xe14+). For the irradiation of 40 keV He+ ions, He bubbles density decreases with decreasing period-thickness. In the case of the irradiation by 6.4 MeV Xe23+ ions, the interface-mixing only appears in the multilayered nanofilm with the largest period-thickness. Under the irradiation with 200 MeV Xe14+ ions, structure damage only occurs in the bottom layers of the multilayered nanofilm with period-thickness of 12 nm. All these experiments show that the Cu/W multilayered nanofilm with the smallest period-thickness possesses the best radiation resistance to ions irradiation with different energies.