Impact of variable energy hydrogen ions on structural and mechanical properties of Zircaloy-4

Abstract

This paper demonstrates hydrogen ion (H+) induced structural and mechanical changes in Zircaloy-4 correlated with its surface morphology. The specimens of Zircaloy-4 were irradiated with H+ at room temperature using a pelletron accelerator. The ion energy was varied from 1 to 4 MeV in four equal steps while keeping the dose fixed at 1 × 1014 H+ cm−2. The range of H+ inside Zircaloy-4, investigated through SRIM software, was 10.4 μm, 29.1 μm, 54.1 μm and 85 μm for 1 MeV, 2 MeV, 3 MeV and 4 MeV irradiated specimens, respectively. X-ray diffraction patterns of irradiated Zircaloy-4 exhibited variations in the width and position of Zr diffraction peaks. The Williamson–Hall analysis of these peaks depicted inconsistent changes in crystallite size and strain with increase of H+ energy. The surface morphology revealed the formation of bubbles and cavities in specimens irradiated with 1 MeV ions. With increasing ion energy above 1 MeV, small cavities and particles clusters were observed. The mechanical testing results indicated an increase in the micro-hardness of the sample irradiated with 1 MeV H+, however, the micro-hardness decreased with increase of ion energy greater than 1 MeV. The obtained results were elucidated on the basis of variable energy H+ interaction with Zircaloy-4 and annihilation of ions induced defects at higher energies.

Sub-5 nm Lithography with Single GeV Heavy Ions Using Inorganic Resist

“…25,26 The MeV ions overcome the drawback of small penetration depth of lowenergy heavy ions while the advantages of high sensitivity and ignorable proximity effect still remain. 27 Therefore, they can produce high-aspect-ratio features with smooth and steep sidewalls. For example, focused MeV proton-beam lithography has shown the capability for fabricating various functional nanostructures that are difficult to achieve using conventional approaches.…”

“…To fully use the advantages of ion beams, extremely high energy (e.g., megaelectronvolts or MeV) ions such as protons and heavy ions can be adopted for lithography. , The MeV ions overcome the drawback of small penetration depth of low-energy heavy ions while the advantages of high sensitivity and ignorable proximity effect still remain . Therefore, they can produce high-aspect-ratio features with smooth and steep sidewalls.…”