Study Of Irradiation Damage Induced By 500KeV He²⁺ion Irradiation In Fe-, Ni- And Ti-based Metallic Glasses

Metallic glass is characterized by arrangement of atoms in long-range disordered and short-range ordered amorphous structure without the lattice defects in conventional crystalline materials, which makes it have the irradiation resistance different from those of conventional crystalline materials, and may be used as an irradiation resistant material in the fusion device. He2+ ion beam irradiated metallic glass strip Fe80Si7.43B 12.57 and Ta38Ni62, bluk metallic glass Ni62.5Nb31.25Ta6.25 and Ti94.3Cu1.9Zr1.9Sn1.9, polycrystalline W, alloy V90.62Cr4.69Ti4.69 and V87.5Cr4.17Ti4.17Nb4.17 with the energy of 500 keV at the fluence of 1×1017,2×1017,5×1017 and 1×1018 ions/cm2, to compare their characteristics of irradiation resistance and to look for metallic glass with a good helium ion irradiation resistance.SRIM program was used for simulating the irradiation process of incident helium ions in Fe80Si7.43B 12.57, Ta38Ni62, Ni62.5Nb31.25Ta6.25, Ti94.3Cu1.9Zr1.9Sn1.9, W, V90.62Cr4.69Ti4.69 and Vg7.5Cr4.17Ti4.17Nb4.17 for range, vacancy, energy loss, sputtering, DPA and distribution of helium concentration. The ranges of helium ions in metallic glass Fe80Si7.43B12.57, Ta38Ni62 and metallic W were 1.04 μm,1.01 μm and 0.76 μm. The peak electron energy loss of metallic glass was smaller than W, the peak vacancy and DPA of metallic glass were bigger than W.Metallic glass Fe80Si7.43B12.57, Ta38Ni62, Ni62.5Nb31.25Ta6.25, Ti94.3Cu1.9Zr1.9Sn1.9 remained amorphous at different fluence of He2+ irradiation. Transmission electron microscopy analysis revealed the presence of tiny helium bubbles near the end of the range of helium ions in the metallic glass Fe80Si7.43B12.57 and Ta38Ni62. Helium bubbles’size was the largest in the central depth of helium bubble layer and reduced gradually to top and bottom sides. No significant damage appeared in the surface of metallic glass. Surface morphology evolution of ion beam irradiated solid material was caused by the process of that the ion bombardment inducing roughness and the material internal transportation inducing smoothness competed with each other. The root mean square roughness of Fe80Si7.43B12.57, Ta38Ni62 and Ti94.3Cu1.9Zr1.9Sn1.9 increased nonlinearly with the increase of fluence. The root mean square roughness of Ni62.5Nb31.25Ta6.25 became greater at the begining and then decreased with the increase of fluence. The metallic glass Fe8oSi7.43B 12.57 kept good soft magnetic properties. The root mean square roughness of polycrystalline W increased and the hardness of polycrystalline W after irradiation increased at first then decreased slightly with the increase of irradiation fluence.At the fluence of 1×18 ions/cm2, all of metallic glasses remained amorphous without significant irradiation damage in the surface, metallic W appeared larger sunken areas in the surface, and alloy V90.62Cr4.69Ti4.69 and V87.5Cr4.17Ti4.17Nb4.17 even occurred multi-layer flaking. The resistance to He2+ ion beam irradiation of metallic glass Fe80Si7.43B 12.57, Ta38Ni62, Ni62.5Nb31.25Ta6.25 and Ti94.3Cu1.9Zr1.9Sn1.9 was better than that of metallic W, and that of metallic W was better than that of alloy V90.62Cr4.69Ti4.69 and V87.5Cr4.17Ti4.17Nb4.17.